From ff112a4750f91475e9eccdb301d7a468e895f6ca Mon Sep 17 00:00:00 2001
From: Jun Yang <harttleharttle@gmail.com>
Date: Mon, 14 Nov 2022 20:51:25 +0800
Subject: [PATCH] chore: rename filters to snake style, #487

BREAKING CHANGE: keys in `<liquidjs>.filters` are now in snake case (instead of camel case), identical to that in Liquid template.
---
 .eslintrc.json                           |  5 +++++
 src/builtin/filters/index.ts             |  7 -------
 src/builtin/filters/url.ts               |  4 ----
 src/{builtin => }/filters/array.ts       | 14 +++++++-------
 src/{builtin => }/filters/date.ts        | 10 +++++-----
 src/{builtin => }/filters/html.ts        |  8 ++++----
 src/filters/index.ts                     | 19 +++++++++++++++++++
 src/{builtin => }/filters/math.ts        |  8 ++++----
 src/{builtin => }/filters/misc.ts        |  6 +++---
 src/{builtin => }/filters/string.ts      | 10 +++++-----
 src/filters/url.ts                       |  4 ++++
 src/liquid-options.ts                    | 13 ++++---------
 src/liquid.ts                            | 10 +++++-----
 src/{builtin => }/tags/assign.ts         |  2 +-
 src/{builtin => }/tags/block.ts          |  6 +++---
 src/{builtin => }/tags/break.ts          |  2 +-
 src/{builtin => }/tags/capture.ts        |  4 ++--
 src/{builtin => }/tags/case.ts           |  4 ++--
 src/{builtin => }/tags/comment.ts        |  6 +++---
 src/{builtin => }/tags/continue.ts       |  2 +-
 src/{builtin => }/tags/cycle.ts          |  6 +++---
 src/{builtin => }/tags/decrement.ts      |  4 ++--
 src/{builtin => }/tags/echo.ts           |  6 +++---
 src/{builtin => }/tags/for.ts            |  8 ++++----
 src/{builtin => }/tags/if.ts             |  2 +-
 src/{builtin => }/tags/include.ts        |  4 ++--
 src/{builtin => }/tags/increment.ts      |  4 ++--
 src/{builtin => }/tags/index.ts          |  6 ++----
 src/{builtin => }/tags/inline-comment.ts |  6 +++---
 src/{builtin => }/tags/layout.ts         |  6 +++---
 src/{builtin => }/tags/liquid.ts         |  6 +++---
 src/{builtin => }/tags/raw.ts            |  2 +-
 src/{builtin => }/tags/render.ts         | 10 +++++-----
 src/{builtin => }/tags/tablerow.ts       |  8 ++++----
 src/{builtin => }/tags/unless.ts         |  2 +-
 src/types.ts                             |  4 ++--
 src/util/underscore.ts                   |  7 -------
 test/unit/util/underscore.ts             |  9 ---------
 38 files changed, 119 insertions(+), 125 deletions(-)
 delete mode 100644 src/builtin/filters/index.ts
 delete mode 100644 src/builtin/filters/url.ts
 rename src/{builtin => }/filters/array.ts (89%)
 rename src/{builtin => }/filters/date.ts (77%)
 rename src/{builtin => }/filters/html.ts (77%)
 create mode 100644 src/filters/index.ts
 rename src/{builtin => }/filters/math.ts (65%)
 rename src/{builtin => }/filters/misc.ts (72%)
 rename src/{builtin => }/filters/string.ts (90%)
 create mode 100644 src/filters/url.ts
 rename src/{builtin => }/tags/assign.ts (96%)
 rename src/{builtin => }/tags/block.ts (91%)
 rename src/{builtin => }/tags/break.ts (69%)
 rename src/{builtin => }/tags/capture.ts (91%)
 rename src/{builtin => }/tags/case.ts (96%)
 rename src/{builtin => }/tags/comment.ts (69%)
 rename src/{builtin => }/tags/continue.ts (69%)
 rename src/{builtin => }/tags/cycle.ts (91%)
 rename src/{builtin => }/tags/decrement.ts (86%)
 rename src/{builtin => }/tags/echo.ts (65%)
 rename src/{builtin => }/tags/for.ts (94%)
 rename src/{builtin => }/tags/if.ts (96%)
 rename src/{builtin => }/tags/include.ts (94%)
 rename src/{builtin => }/tags/increment.ts (87%)
 rename src/{builtin => }/tags/index.ts (85%)
 rename src/{builtin => }/tags/inline-comment.ts (59%)
 rename src/{builtin => }/tags/layout.ts (91%)
 rename src/{builtin => }/tags/liquid.ts (73%)
 rename src/{builtin => }/tags/raw.ts (89%)
 rename src/{builtin => }/tags/render.ts (95%)
 rename src/{builtin => }/tags/tablerow.ts (89%)
 rename src/{builtin => }/tags/unless.ts (95%)

diff --git a/.eslintrc.json b/.eslintrc.json
index 4008221b3e..66b32c6ce9 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -37,6 +37,11 @@
     "@typescript-eslint/no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": false }]
   },
   "overrides": [{
+    "files": ["**/filters/*.ts"],
+    "rules": {
+      "camelcase": "off"
+    }
+  }, {
     "files": ["**/*.js", "**/*.mjs"],
     "rules": {
       "@typescript-eslint/no-var-requires": "off"
diff --git a/src/builtin/filters/index.ts b/src/builtin/filters/index.ts
deleted file mode 100644
index 2219dee48a..0000000000
--- a/src/builtin/filters/index.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-export * from './html'
-export * from './math'
-export * from './url'
-export * from './array'
-export * from './date'
-export * from './misc'
-export * from './string'
diff --git a/src/builtin/filters/url.ts b/src/builtin/filters/url.ts
deleted file mode 100644
index 087a6de276..0000000000
--- a/src/builtin/filters/url.ts
+++ /dev/null
@@ -1,4 +0,0 @@
-import { stringify } from '../../util/underscore'
-
-export const urlDecode = (x: string) => stringify(x).split('+').map(decodeURIComponent).join(' ')
-export const urlEncode = (x: string) => stringify(x).split(' ').map(encodeURIComponent).join('+')
diff --git a/src/builtin/filters/array.ts b/src/filters/array.ts
similarity index 89%
rename from src/builtin/filters/array.ts
rename to src/filters/array.ts
index 8c444ee3b2..a7ae807b0f 100644
--- a/src/builtin/filters/array.ts
+++ b/src/filters/array.ts
@@ -1,9 +1,9 @@
-import { argumentsToValue, toValue, stringify, caseInsensitiveCompare, isArray, isNil, last as arrayLast, hasOwnProperty } from '../../util/underscore'
-import { toArray } from '../../util/collection'
-import { isTruthy } from '../../render/boolean'
-import { FilterImpl } from '../../template/filter/filter-impl'
-import { Scope } from '../../context/scope'
-import { isComparable } from '../../drop/comparable'
+import { argumentsToValue, toValue, stringify, caseInsensitiveCompare, isArray, isNil, last as arrayLast, hasOwnProperty } from '../util/underscore'
+import { toArray } from '../util/collection'
+import { isTruthy } from '../render/boolean'
+import { FilterImpl } from '../template/filter/filter-impl'
+import { Scope } from '../context/scope'
+import { isComparable } from '../drop/comparable'
 
 export const join = argumentsToValue((v: any[], arg: string) => toArray(v).join(arg === undefined ? ' ' : arg))
 export const last = argumentsToValue((v: any) => isArray(v) ? arrayLast(v) : '')
@@ -25,7 +25,7 @@ export function * sort<T> (this: FilterImpl, arr: T[], property?: string): Itera
   }).map(tuple => tuple[0])
 }
 
-export function sortNatural<T> (input: T[], property?: string) {
+export function sort_natural<T> (input: T[], property?: string) {
   input = toValue(input)
   const propertyString = stringify(property)
   const compare = property === undefined
diff --git a/src/builtin/filters/date.ts b/src/filters/date.ts
similarity index 77%
rename from src/builtin/filters/date.ts
rename to src/filters/date.ts
index 59f1df9584..6c1a9af9b8 100644
--- a/src/builtin/filters/date.ts
+++ b/src/filters/date.ts
@@ -1,8 +1,8 @@
-import strftime from '../../util/strftime'
-import { LiquidDate } from '../../util/liquid-date'
-import { toValue, stringify, isString, isNumber } from '../../util/underscore'
-import { FilterImpl } from '../../template/filter/filter-impl'
-import { TimezoneDate } from '../../util/timezone-date'
+import strftime from '../util/strftime'
+import { LiquidDate } from '../util/liquid-date'
+import { toValue, stringify, isString, isNumber } from '../util/underscore'
+import { FilterImpl } from '../template/filter/filter-impl'
+import { TimezoneDate } from '../util/timezone-date'
 
 export function date (this: FilterImpl, v: string | Date, format: string, timeZoneOffset?: number) {
   const opts = this.context.opts
diff --git a/src/builtin/filters/html.ts b/src/filters/html.ts
similarity index 77%
rename from src/builtin/filters/html.ts
rename to src/filters/html.ts
index cdb340fe91..36b57b2a40 100644
--- a/src/builtin/filters/html.ts
+++ b/src/filters/html.ts
@@ -1,4 +1,4 @@
-import { stringify } from '../../util/underscore'
+import { stringify } from '../util/underscore'
 
 const escapeMap = {
   '&': '&amp;',
@@ -23,14 +23,14 @@ function unescape (str: string) {
   return stringify(str).replace(/&(amp|lt|gt|#34|#39);/g, m => unescapeMap[m])
 }
 
-export function escapeOnce (str: string) {
+export function escape_once (str: string) {
   return escape(unescape(stringify(str)))
 }
 
-export function newlineToBr (v: string) {
+export function newline_to_br (v: string) {
   return stringify(v).replace(/\n/g, '<br />\n')
 }
 
-export function stripHtml (v: string) {
+export function strip_html (v: string) {
   return stringify(v).replace(/<script.*?<\/script>|<!--.*?-->|<style.*?<\/style>|<.*?>/g, '')
 }
diff --git a/src/filters/index.ts b/src/filters/index.ts
new file mode 100644
index 0000000000..8fa56176e2
--- /dev/null
+++ b/src/filters/index.ts
@@ -0,0 +1,19 @@
+import * as htmlFilters from './html'
+import * as mathFilters from './math'
+import * as urlFilters from './url'
+import * as arrayFilters from './array'
+import * as dateFilters from './date'
+import * as stringFilters from './string'
+import { Default, json } from './misc'
+import { FilterImplOptions } from '../template/filter/filter-impl-options'
+
+export const filters: { [key: string]: FilterImplOptions } = {
+  ...htmlFilters,
+  ...mathFilters,
+  ...urlFilters,
+  ...arrayFilters,
+  ...dateFilters,
+  ...stringFilters,
+  json,
+  default: Default
+}
diff --git a/src/builtin/filters/math.ts b/src/filters/math.ts
similarity index 65%
rename from src/builtin/filters/math.ts
rename to src/filters/math.ts
index 28be0cf822..b009532064 100644
--- a/src/builtin/filters/math.ts
+++ b/src/filters/math.ts
@@ -1,10 +1,10 @@
-import { toValue, argumentsToValue } from '../../util/underscore'
+import { toValue, argumentsToValue } from '../util/underscore'
 
 export const abs = argumentsToValue(Math.abs)
-export const atLeast = argumentsToValue(Math.max)
-export const atMost = argumentsToValue(Math.min)
+export const at_least = argumentsToValue(Math.max)
+export const at_most = argumentsToValue(Math.min)
 export const ceil = argumentsToValue(Math.ceil)
-export const dividedBy = argumentsToValue((dividend: number, divisor: number, integerArithmetic = false) => integerArithmetic ? Math.floor(dividend / divisor) : dividend / divisor)
+export const divided_by = argumentsToValue((dividend: number, divisor: number, integerArithmetic = false) => integerArithmetic ? Math.floor(dividend / divisor) : dividend / divisor)
 export const floor = argumentsToValue(Math.floor)
 export const minus = argumentsToValue((v: number, arg: number) => v - arg)
 export const modulo = argumentsToValue((v: number, arg: number) => v % arg)
diff --git a/src/builtin/filters/misc.ts b/src/filters/misc.ts
similarity index 72%
rename from src/builtin/filters/misc.ts
rename to src/filters/misc.ts
index be7b1a936e..a6b9619f8c 100644
--- a/src/builtin/filters/misc.ts
+++ b/src/filters/misc.ts
@@ -1,6 +1,6 @@
-import { isFalsy } from '../../render/boolean'
-import { identify, isArray, isString, toValue } from '../../util/underscore'
-import { FilterImpl } from '../../template/filter/filter-impl'
+import { isFalsy } from '../render/boolean'
+import { identify, isArray, isString, toValue } from '../util/underscore'
+import { FilterImpl } from '../template/filter/filter-impl'
 
 export function Default<T1 extends boolean, T2> (this: FilterImpl, value: T1, defaultValue: T2, ...args: Array<[string, any]>): T1 | T2 {
   value = toValue(value)
diff --git a/src/builtin/filters/string.ts b/src/filters/string.ts
similarity index 90%
rename from src/builtin/filters/string.ts
rename to src/filters/string.ts
index faf042bf90..49ff3cb6dc 100644
--- a/src/builtin/filters/string.ts
+++ b/src/filters/string.ts
@@ -3,8 +3,8 @@
  *
  * * prefer stringify() to String() since `undefined`, `null` should eval ''
  */
-import { escapeRegExp, stringify } from '../../util/underscore'
-import { assert } from '../../util/assert'
+import { escapeRegExp, stringify } from '../util/underscore'
+import { assert } from '../util/assert'
 
 export function append (v: string, arg: string) {
   assert(arguments.length === 2, 'append expect 2 arguments')
@@ -36,7 +36,7 @@ export function remove (v: string, arg: string) {
   return stringify(v).split(String(arg)).join('')
 }
 
-export function removeFirst (v: string, l: string) {
+export function remove_first (v: string, l: string) {
   return stringify(v).replace(String(l), '')
 }
 
@@ -66,7 +66,7 @@ export function strip (v: string, chars?: string) {
   return stringify(v).trim()
 }
 
-export function stripNewlines (v: string) {
+export function strip_newlines (v: string) {
   return stringify(v).replace(/\n/g, '')
 }
 
@@ -79,7 +79,7 @@ export function replace (v: string, pattern: string, replacement: string) {
   return stringify(v).split(String(pattern)).join(replacement)
 }
 
-export function replaceFirst (v: string, arg1: string, arg2: string) {
+export function replace_first (v: string, arg1: string, arg2: string) {
   return stringify(v).replace(String(arg1), arg2)
 }
 
diff --git a/src/filters/url.ts b/src/filters/url.ts
new file mode 100644
index 0000000000..c5719099e6
--- /dev/null
+++ b/src/filters/url.ts
@@ -0,0 +1,4 @@
+import { stringify } from '../util/underscore'
+
+export const url_decode = (x: string) => stringify(x).split('+').map(decodeURIComponent).join(' ')
+export const url_encode = (x: string) => stringify(x).split(' ').map(encodeURIComponent).join('+')
diff --git a/src/liquid-options.ts b/src/liquid-options.ts
index 9dd1c7a4d6..bf91548752 100644
--- a/src/liquid-options.ts
+++ b/src/liquid-options.ts
@@ -1,17 +1,12 @@
-import { snakeCase, forOwn, isArray, isString, isFunction } from './util/underscore'
+import { isArray, isString, isFunction } from './util/underscore'
 import { LiquidCache } from './cache/cache'
 import { LRU } from './cache/lru'
 import { FS } from './fs/fs'
 import * as fs from './fs/node'
 import { defaultOperators, Operators } from './render/operator'
 import { createTrie, Trie } from './util/operator-trie'
-import * as builtinFilters from './builtin/filters'
-import { assert, FilterImplOptions } from './types'
-
-const filters = new Map()
-forOwn(builtinFilters, (conf: FilterImplOptions, name: string) => {
-  filters.set(snakeCase(name), conf)
-})
+import { filters } from './filters'
+import { assert } from './types'
 
 type OutputEscape = (value: any) => string
 type OutputEscapeOption = 'escape' | 'json' | OutputEscape
@@ -198,7 +193,7 @@ export function normalize (options: LiquidOptions): NormalizedFullOptions {
 
 function getOutputEscapeFunction (nameOrFunction: OutputEscapeOption) {
   if (isString(nameOrFunction)) {
-    const filterImpl = filters.get(nameOrFunction)
+    const filterImpl = filters[nameOrFunction]
     assert(isFunction(filterImpl), `filter "${nameOrFunction}" not found`)
     return filterImpl
   } else {
diff --git a/src/liquid.ts b/src/liquid.ts
index 3e1536ce5e..c0e1a69800 100644
--- a/src/liquid.ts
+++ b/src/liquid.ts
@@ -1,13 +1,13 @@
 import { Context } from './context/context'
-import { forOwn, snakeCase } from './util/underscore'
+import { forOwn } from './util/underscore'
 import { Template } from './template/template'
 import { LookupType } from './fs/loader'
 import { Render } from './render/render'
 import Parser from './parser/parser'
 import { TagImplOptions } from './template/tag/tag-impl-options'
 import { Value } from './template/value'
-import builtinTags from './builtin/tags'
-import * as builtinFilters from './builtin/filters'
+import { tags } from './tags'
+import { filters } from './filters'
 import { TagMap } from './template/tag/tag-map'
 import { FilterMap } from './template/filter/filter-map'
 import { LiquidOptions, normalizeDirectoryList, NormalizedFullOptions, normalize, RenderOptions } from './liquid-options'
@@ -32,8 +32,8 @@ export class Liquid {
     this.filters = new FilterMap(this.options.strictFilters, this)
     this.tags = new TagMap()
 
-    forOwn(builtinTags, (conf: TagImplOptions, name: string) => this.registerTag(snakeCase(name), conf))
-    forOwn(builtinFilters, (handler: FilterImplOptions, name: string) => this.registerFilter(snakeCase(name), handler))
+    forOwn(tags, (conf: TagImplOptions, name: string) => this.registerTag(name, conf))
+    forOwn(filters, (handler: FilterImplOptions, name: string) => this.registerFilter(name, handler))
   }
   public parse (html: string, filepath?: string): Template[] {
     return this.parser.parse(html, filepath)
diff --git a/src/builtin/tags/assign.ts b/src/tags/assign.ts
similarity index 96%
rename from src/builtin/tags/assign.ts
rename to src/tags/assign.ts
index 8891105137..82f08d766c 100644
--- a/src/builtin/tags/assign.ts
+++ b/src/tags/assign.ts
@@ -1,4 +1,4 @@
-import { Value, Tokenizer, assert, TagImplOptions, TagToken, Context } from '../../types'
+import { Value, Tokenizer, assert, TagImplOptions, TagToken, Context } from '../types'
 
 export default {
   parse: function (token: TagToken) {
diff --git a/src/builtin/tags/block.ts b/src/tags/block.ts
similarity index 91%
rename from src/builtin/tags/block.ts
rename to src/tags/block.ts
index d966017baa..ec3ba67040 100644
--- a/src/builtin/tags/block.ts
+++ b/src/tags/block.ts
@@ -1,6 +1,6 @@
-import BlockMode from '../../context/block-mode'
-import { BlockDrop } from '../../drop/block-drop'
-import { TagToken, TopLevelToken, Template, Context, TagImpl, Emitter } from '../../types'
+import BlockMode from '../context/block-mode'
+import { BlockDrop } from '../drop/block-drop'
+import { TagToken, TopLevelToken, Template, Context, TagImpl, Emitter } from '../types'
 
 export default {
   parse (this: TagImpl, token: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/break.ts b/src/tags/break.ts
similarity index 69%
rename from src/builtin/tags/break.ts
rename to src/tags/break.ts
index bfa8450c9f..fc73ce7ff8 100644
--- a/src/builtin/tags/break.ts
+++ b/src/tags/break.ts
@@ -1,4 +1,4 @@
-import { Emitter, Context } from '../../types'
+import { Emitter, Context } from '../types'
 
 export default {
   render: function (ctx: Context, emitter: Emitter) {
diff --git a/src/builtin/tags/capture.ts b/src/tags/capture.ts
similarity index 91%
rename from src/builtin/tags/capture.ts
rename to src/tags/capture.ts
index 5e17870256..3dde40d376 100644
--- a/src/builtin/tags/capture.ts
+++ b/src/tags/capture.ts
@@ -1,5 +1,5 @@
-import { Tokenizer, assert, Template, Context, TagImplOptions, TagToken, TopLevelToken } from '../../types'
-import { evalQuotedToken } from '../../render/expression'
+import { Tokenizer, assert, Template, Context, TagImplOptions, TagToken, TopLevelToken } from '../types'
+import { evalQuotedToken } from '../render/expression'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/case.ts b/src/tags/case.ts
similarity index 96%
rename from src/builtin/tags/case.ts
rename to src/tags/case.ts
index d779fe8ffb..742d011350 100644
--- a/src/builtin/tags/case.ts
+++ b/src/tags/case.ts
@@ -1,5 +1,5 @@
-import { toValue, _evalToken, Value, Emitter, TagToken, TopLevelToken, Context, Template, TagImplOptions, ParseStream } from '../../types'
-import { Tokenizer } from '../../parser/tokenizer'
+import { toValue, _evalToken, Value, Emitter, TagToken, TopLevelToken, Context, Template, TagImplOptions, ParseStream } from '../types'
+import { Tokenizer } from '../parser/tokenizer'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/comment.ts b/src/tags/comment.ts
similarity index 69%
rename from src/builtin/tags/comment.ts
rename to src/tags/comment.ts
index dacb19fa9d..0c07446739 100644
--- a/src/builtin/tags/comment.ts
+++ b/src/tags/comment.ts
@@ -1,6 +1,6 @@
-import { TagToken } from '../../tokens/tag-token'
-import { TopLevelToken } from '../../tokens/toplevel-token'
-import { TagImplOptions } from '../../template/tag/tag-impl-options'
+import { TagToken } from '../tokens/tag-token'
+import { TopLevelToken } from '../tokens/toplevel-token'
+import { TagImplOptions } from '../template/tag/tag-impl-options'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/continue.ts b/src/tags/continue.ts
similarity index 69%
rename from src/builtin/tags/continue.ts
rename to src/tags/continue.ts
index 1f5b28cd7e..ce92d96701 100644
--- a/src/builtin/tags/continue.ts
+++ b/src/tags/continue.ts
@@ -1,4 +1,4 @@
-import { Emitter, Context } from '../../types'
+import { Emitter, Context } from '../types'
 
 export default {
   render: function (ctx: Context, emitter: Emitter) {
diff --git a/src/builtin/tags/cycle.ts b/src/tags/cycle.ts
similarity index 91%
rename from src/builtin/tags/cycle.ts
rename to src/tags/cycle.ts
index b4f05cc363..a542df1099 100644
--- a/src/builtin/tags/cycle.ts
+++ b/src/tags/cycle.ts
@@ -1,6 +1,6 @@
-import { assert } from '../../util/assert'
-import { _evalToken, Emitter, TagToken, Context, TagImplOptions } from '../../types'
-import { Tokenizer } from '../../parser/tokenizer'
+import { assert } from '../util/assert'
+import { _evalToken, Emitter, TagToken, Context, TagImplOptions } from '../types'
+import { Tokenizer } from '../parser/tokenizer'
 
 export default {
   parse: function (tagToken: TagToken) {
diff --git a/src/builtin/tags/decrement.ts b/src/tags/decrement.ts
similarity index 86%
rename from src/builtin/tags/decrement.ts
rename to src/tags/decrement.ts
index 6c05506e57..b8b3c49557 100644
--- a/src/builtin/tags/decrement.ts
+++ b/src/tags/decrement.ts
@@ -1,5 +1,5 @@
-import { Tokenizer, Emitter, TagToken, Context, TagImplOptions } from '../../types'
-import { isNumber, stringify } from '../../util/underscore'
+import { Tokenizer, Emitter, TagToken, Context, TagImplOptions } from '../types'
+import { isNumber, stringify } from '../util/underscore'
 
 export default {
   parse: function (token: TagToken) {
diff --git a/src/builtin/tags/echo.ts b/src/tags/echo.ts
similarity index 65%
rename from src/builtin/tags/echo.ts
rename to src/tags/echo.ts
index fee2b81ab4..4ed8805c2c 100644
--- a/src/builtin/tags/echo.ts
+++ b/src/tags/echo.ts
@@ -1,6 +1,6 @@
-import { Value } from '../../template/value'
-import { Emitter } from '../../emitters/emitter'
-import { TagImplOptions, TagToken, Context } from '../../types'
+import { Value } from '../template/value'
+import { Emitter } from '../emitters/emitter'
+import { TagImplOptions, TagToken, Context } from '../types'
 
 export default {
   parse: function (token: TagToken) {
diff --git a/src/builtin/tags/for.ts b/src/tags/for.ts
similarity index 94%
rename from src/builtin/tags/for.ts
rename to src/tags/for.ts
index 64535ac55c..2c47ddffcd 100644
--- a/src/builtin/tags/for.ts
+++ b/src/tags/for.ts
@@ -1,7 +1,7 @@
-import { assert, Tokenizer, _evalToken, Emitter, TagToken, TopLevelToken, Context, Template, TagImplOptions, ParseStream } from '../../types'
-import { toEnumerable } from '../../util/collection'
-import { ForloopDrop } from '../../drop/forloop-drop'
-import { Hash, HashValue } from '../../template/tag/hash'
+import { assert, Tokenizer, _evalToken, Emitter, TagToken, TopLevelToken, Context, Template, TagImplOptions, ParseStream } from '../types'
+import { toEnumerable } from '../util/collection'
+import { ForloopDrop } from '../drop/forloop-drop'
+import { Hash, HashValue } from '../template/tag/hash'
 
 const MODIFIERS = ['offset', 'limit', 'reversed']
 
diff --git a/src/builtin/tags/if.ts b/src/tags/if.ts
similarity index 96%
rename from src/builtin/tags/if.ts
rename to src/tags/if.ts
index 7ba72ddde4..4aba47b510 100644
--- a/src/builtin/tags/if.ts
+++ b/src/tags/if.ts
@@ -1,4 +1,4 @@
-import { Value, Emitter, isTruthy, TagToken, TopLevelToken, Context, Template, TagImplOptions } from '../../types'
+import { Value, Emitter, isTruthy, TagToken, TopLevelToken, Context, Template, TagImplOptions } from '../types'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/include.ts b/src/tags/include.ts
similarity index 94%
rename from src/builtin/tags/include.ts
rename to src/tags/include.ts
index 7432afce94..87cb7b13c2 100644
--- a/src/builtin/tags/include.ts
+++ b/src/tags/include.ts
@@ -1,5 +1,5 @@
-import { assert, Tokenizer, _evalToken, Hash, Emitter, TagToken, Context, TagImplOptions } from '../../types'
-import BlockMode from '../../context/block-mode'
+import { assert, Tokenizer, _evalToken, Hash, Emitter, TagToken, Context, TagImplOptions } from '../types'
+import BlockMode from '../context/block-mode'
 import { parseFilePath, renderFilePath } from './render'
 
 export default {
diff --git a/src/builtin/tags/increment.ts b/src/tags/increment.ts
similarity index 87%
rename from src/builtin/tags/increment.ts
rename to src/tags/increment.ts
index 1fdc61605c..5cde2dc34d 100644
--- a/src/builtin/tags/increment.ts
+++ b/src/tags/increment.ts
@@ -1,5 +1,5 @@
-import { isNumber, stringify } from '../../util/underscore'
-import { Tokenizer, Emitter, TagToken, Context, TagImplOptions } from '../../types'
+import { isNumber, stringify } from '../util/underscore'
+import { Tokenizer, Emitter, TagToken, Context, TagImplOptions } from '../types'
 
 export default {
   parse: function (token: TagToken) {
diff --git a/src/builtin/tags/index.ts b/src/tags/index.ts
similarity index 85%
rename from src/builtin/tags/index.ts
rename to src/tags/index.ts
index 82ec5b4a49..19e6e3ac4f 100644
--- a/src/builtin/tags/index.ts
+++ b/src/tags/index.ts
@@ -19,10 +19,8 @@ import Continue from './continue'
 import echo from './echo'
 import liquid from './liquid'
 import inlineComment from './inline-comment'
-import { TagImplOptions } from '../../template/tag/tag-impl-options'
+import { TagImplOptions } from '../template/tag/tag-impl-options'
 
-const tags: { [key: string]: TagImplOptions } = {
+export const tags: { [key: string]: TagImplOptions } = {
   assign, 'for': For, capture, 'case': Case, comment, include, render, decrement, increment, cycle, 'if': If, layout, block, raw, tablerow, unless, 'break': Break, 'continue': Continue, echo, liquid, '#': inlineComment
 }
-
-export default tags
diff --git a/src/builtin/tags/inline-comment.ts b/src/tags/inline-comment.ts
similarity index 59%
rename from src/builtin/tags/inline-comment.ts
rename to src/tags/inline-comment.ts
index 755d4ca3f2..2a1d740d20 100644
--- a/src/builtin/tags/inline-comment.ts
+++ b/src/tags/inline-comment.ts
@@ -1,6 +1,6 @@
-import { TagToken } from '../../tokens/tag-token'
-import { TopLevelToken } from '../../tokens/toplevel-token'
-import { TagImplOptions } from '../../template/tag/tag-impl-options'
+import { TagToken } from '../tokens/tag-token'
+import { TopLevelToken } from '../tokens/toplevel-token'
+import { TagImplOptions } from '../template/tag/tag-impl-options'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/layout.ts b/src/tags/layout.ts
similarity index 91%
rename from src/builtin/tags/layout.ts
rename to src/tags/layout.ts
index 87c0a20246..fc5d618fd0 100644
--- a/src/builtin/tags/layout.ts
+++ b/src/tags/layout.ts
@@ -1,7 +1,7 @@
-import { assert, Tokenizer, Emitter, Hash, TagToken, TopLevelToken, Context, TagImplOptions } from '../../types'
-import BlockMode from '../../context/block-mode'
+import { assert, Tokenizer, Emitter, Hash, TagToken, TopLevelToken, Context, TagImplOptions } from '../types'
+import BlockMode from '../context/block-mode'
 import { parseFilePath, renderFilePath } from './render'
-import { BlankDrop } from '../../drop/blank-drop'
+import { BlankDrop } from '../drop/blank-drop'
 
 export default {
   parseFilePath,
diff --git a/src/builtin/tags/liquid.ts b/src/tags/liquid.ts
similarity index 73%
rename from src/builtin/tags/liquid.ts
rename to src/tags/liquid.ts
index 55294254c3..00be32fb28 100644
--- a/src/builtin/tags/liquid.ts
+++ b/src/tags/liquid.ts
@@ -1,6 +1,6 @@
-import { Emitter } from '../../emitters/emitter'
-import { TagImplOptions, TagToken, Context } from '../../types'
-import { Tokenizer } from '../../parser/tokenizer'
+import { Emitter } from '../emitters/emitter'
+import { TagImplOptions, TagToken, Context } from '../types'
+import { Tokenizer } from '../parser/tokenizer'
 
 export default {
   parse: function (token: TagToken) {
diff --git a/src/builtin/tags/raw.ts b/src/tags/raw.ts
similarity index 89%
rename from src/builtin/tags/raw.ts
rename to src/tags/raw.ts
index 1aa5d1bf6a..41cbeda52b 100644
--- a/src/builtin/tags/raw.ts
+++ b/src/tags/raw.ts
@@ -1,4 +1,4 @@
-import { TagToken, TopLevelToken, TagImplOptions } from '../../types'
+import { TagToken, TopLevelToken, TagImplOptions } from '../types'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/render.ts b/src/tags/render.ts
similarity index 95%
rename from src/builtin/tags/render.ts
rename to src/tags/render.ts
index 97268d6697..eb9033953c 100644
--- a/src/builtin/tags/render.ts
+++ b/src/tags/render.ts
@@ -1,9 +1,9 @@
 import { __assign } from 'tslib'
-import { assert } from '../../util/assert'
-import { ForloopDrop } from '../../drop/forloop-drop'
-import { toEnumerable } from '../../util/collection'
-import { Liquid } from '../../liquid'
-import { Token, Template, evalQuotedToken, TypeGuards, Tokenizer, _evalToken, Hash, Emitter, TagToken, Context, TagImplOptions } from '../../types'
+import { assert } from '../util/assert'
+import { ForloopDrop } from '../drop/forloop-drop'
+import { toEnumerable } from '../util/collection'
+import { Liquid } from '../liquid'
+import { Token, Template, evalQuotedToken, TypeGuards, Tokenizer, _evalToken, Hash, Emitter, TagToken, Context, TagImplOptions } from '../types'
 
 export default {
   parseFilePath,
diff --git a/src/builtin/tags/tablerow.ts b/src/tags/tablerow.ts
similarity index 89%
rename from src/builtin/tags/tablerow.ts
rename to src/tags/tablerow.ts
index 900a241b70..0fc17fa617 100644
--- a/src/builtin/tags/tablerow.ts
+++ b/src/tags/tablerow.ts
@@ -1,7 +1,7 @@
-import { toEnumerable } from '../../util/collection'
-import { assert, _evalToken, Emitter, Hash, TagToken, TopLevelToken, Context, Template, TagImplOptions, ParseStream } from '../../types'
-import { TablerowloopDrop } from '../../drop/tablerowloop-drop'
-import { Tokenizer } from '../../parser/tokenizer'
+import { toEnumerable } from '../util/collection'
+import { assert, _evalToken, Emitter, Hash, TagToken, TopLevelToken, Context, Template, TagImplOptions, ParseStream } from '../types'
+import { TablerowloopDrop } from '../drop/tablerowloop-drop'
+import { Tokenizer } from '../parser/tokenizer'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/builtin/tags/unless.ts b/src/tags/unless.ts
similarity index 95%
rename from src/builtin/tags/unless.ts
rename to src/tags/unless.ts
index 54ed7d63ec..8c0465921e 100644
--- a/src/builtin/tags/unless.ts
+++ b/src/tags/unless.ts
@@ -1,4 +1,4 @@
-import { Value, TopLevelToken, Template, Emitter, isTruthy, isFalsy, Context, TagImplOptions, TagToken } from '../../types'
+import { Value, TopLevelToken, Template, Emitter, isTruthy, isFalsy, Context, TagImplOptions, TagToken } from '../types'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: TopLevelToken[]) {
diff --git a/src/types.ts b/src/types.ts
index 62040703ea..1a24849e32 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -27,6 +27,6 @@ export { defaultOperators, Operators } from './render/operator'
 export { createTrie, Trie } from './util/operator-trie'
 export { toValue } from './util/underscore'
 export { TimezoneDate } from './util/timezone-date'
-export * as filters from './builtin/filters'
-export * as tags from './builtin/tags'
+export { filters } from './filters'
+export { tags } from './tags'
 export { defaultOptions } from './liquid-options'
diff --git a/src/util/underscore.ts b/src/util/underscore.ts
index 96f80c35d0..fd679fc4e1 100644
--- a/src/util/underscore.ts
+++ b/src/util/underscore.ts
@@ -137,13 +137,6 @@ export function identify<T> (val: T): T {
   return val
 }
 
-export function snakeCase (str: string) {
-  return str.replace(
-    /(\w?)([A-Z])/g,
-    (_, a, b) => (a ? a + '_' : '') + b.toLowerCase()
-  )
-}
-
 export function changeCase (str: string): string {
   const hasLowerCase = [...str].some(ch => ch >= 'a' && ch <= 'z')
   return hasLowerCase ? str.toUpperCase() : str.toLowerCase()
diff --git a/test/unit/util/underscore.ts b/test/unit/util/underscore.ts
index 623024e8de..844960d966 100644
--- a/test/unit/util/underscore.ts
+++ b/test/unit/util/underscore.ts
@@ -7,15 +7,6 @@ const expect = chai.expect
 chai.use(sinonChai)
 
 describe('util/underscore', function () {
-  describe('.camel2snake()', function () {
-    it('should convert camelCase to snakeCase', function () {
-      expect(_.snakeCase('fooBarCoo')).to.equal('foo_bar_coo')
-    })
-    it('should convert empty string to empty string', function () {
-      expect(_.snakeCase('')).to.equal('')
-    })
-  })
-
   describe('.isString()', function () {
     it('should return true for literal string', function () {
       expect(_.isString('foo')).to.be.true