feat: move tag.createNode to static nodeClass.from

Re: eemeli#457

src/doc/createNode.ts

@@ -99,6 +99,8 @@ export function createNode(
 
   const node = tagObj?.createNode
     ? tagObj.createNode(ctx.schema, value, ctx)
+    : typeof tagObj?.nodeClass?.from === 'function'
+    ? tagObj.nodeClass.from(ctx.schema, value, ctx)
     : new Scalar(value)
   if (tagName) node.tag = tagName
   else if (!tagObj.default) node.tag = tagObj.tag

src/nodes/YAMLMap.ts

@@ -2,11 +2,12 @@ import type { BlockMap, FlowCollection } from '../parse/cst.js'
 import type { Schema } from '../schema/Schema.js'
 import type { StringifyContext } from '../stringify/stringify.js'
 import { stringifyCollection } from '../stringify/stringifyCollection.js'
+import { CreateNodeContext } from '../util.js'
 import { addPairToJSMap } from './addPairToJSMap.js'
 import { Collection } from './Collection.js'
 import { isPair, isScalar, MAP } from './identity.js'
 import type { ParsedNode, Range } from './Node.js'
-import { Pair } from './Pair.js'
+import { createPair, Pair } from './Pair.js'
 import { isScalarValue, Scalar } from './Scalar.js'
 import type { ToJSContext } from './toJS.js'
 
@@ -51,6 +52,30 @@ export class YAMLMap<K = unknown, V = unknown> extends Collection {
     super(MAP, schema)
   }
 
+  /**
+   * A generic collection parsing method that can be extended
+   * to other node classes that inherit from YAMLMap
+   */
+  static from(schema: Schema, obj: unknown, ctx: CreateNodeContext) {
+    const { keepUndefined, replacer } = ctx
+    const map = new this(schema)
+    const add = (key: unknown, value: unknown) => {
+      if (typeof replacer === 'function') value = replacer.call(obj, key, value)
+      else if (Array.isArray(replacer) && !replacer.includes(key)) return
+      if (value !== undefined || keepUndefined)
+        map.items.push(createPair(key, value, ctx))
+    }
+    if (obj instanceof Map) {
+      for (const [key, value] of obj) add(key, value)
+    } else if (obj && typeof obj === 'object') {
+      for (const key of Object.keys(obj)) add(key, (obj as any)[key])
+    }
+    if (typeof schema.sortMapEntries === 'function') {
+      map.items.sort(schema.sortMapEntries)
+    }
+    return map
+  }
+
   /**
    * Adds a value to the collection.
    *

src/nodes/YAMLSeq.ts

@@ -2,6 +2,7 @@ import type { BlockSequence, FlowCollection } from '../parse/cst.js'
 import type { Schema } from '../schema/Schema.js'
 import type { StringifyContext } from '../stringify/stringify.js'
 import { stringifyCollection } from '../stringify/stringifyCollection.js'
+import { createNode, CreateNodeContext } from '../util.js'
 import { Collection } from './Collection.js'
 import { isScalar, SEQ } from './identity.js'
 import type { ParsedNode, Range } from './Node.js'
@@ -116,6 +117,22 @@ export class YAMLSeq<T = unknown> extends Collection {
       onComment
     })
   }
+
+  static from(schema: Schema, obj: unknown, ctx: CreateNodeContext) {
+    const { replacer } = ctx
+    const seq = new YAMLSeq(schema)
+    if (obj && Symbol.iterator in Object(obj)) {
+      let i = 0
+      for (let it of obj as Iterable<unknown>) {
+        if (typeof replacer === 'function') {
+          const key = obj instanceof Set ? it : String(i++)
+          it = replacer.call(obj, key, it)
+        }
+        seq.items.push(createNode(it, undefined, ctx))
+      }
+    }
+    return seq
+  }
 }
 
 function asItemIndex(key: unknown): number | null {

src/schema/common/map.ts

@@ -1,38 +1,15 @@
-import type { CreateNodeContext } from '../../doc/createNode.js'
 import { isMap } from '../../nodes/identity.js'
-import { createPair } from '../../nodes/Pair.js'
 import { YAMLMap } from '../../nodes/YAMLMap.js'
 import type { CollectionTag } from '../types.js'
-import type { Schema } from '../Schema.js'
-
-function createMap(schema: Schema, obj: unknown, ctx: CreateNodeContext) {
-  const { keepUndefined, replacer } = ctx
-  const map = new YAMLMap(schema)
-  const add = (key: unknown, value: unknown) => {
-    if (typeof replacer === 'function') value = replacer.call(obj, key, value)
-    else if (Array.isArray(replacer) && !replacer.includes(key)) return
-    if (value !== undefined || keepUndefined)
-      map.items.push(createPair(key, value, ctx))
-  }
-  if (obj instanceof Map) {
-    for (const [key, value] of obj) add(key, value)
-  } else if (obj && typeof obj === 'object') {
-    for (const key of Object.keys(obj)) add(key, (obj as any)[key])
-  }
-  if (typeof schema.sortMapEntries === 'function') {
-    map.items.sort(schema.sortMapEntries)
-  }
-  return map
-}
 
 export const map: CollectionTag = {
   collection: 'map',
-  createNode: createMap,
   default: true,
   nodeClass: YAMLMap,
   tag: 'tag:yaml.org,2002:map',
   resolve(map, onError) {
     if (!isMap(map)) onError('Expected a mapping for this tag')
     return map
-  }
+  },
+  createNode: (schema, obj, ctx) => YAMLMap.from(schema, obj, ctx),
 }

src/schema/common/seq.ts

@@ -1,33 +1,15 @@
-import { CreateNodeContext, createNode } from '../../doc/createNode.js'
 import { isSeq } from '../../nodes/identity.js'
 import { YAMLSeq } from '../../nodes/YAMLSeq.js'
-import type { Schema } from '../Schema.js'
 import type { CollectionTag } from '../types.js'
 
-function createSeq(schema: Schema, obj: unknown, ctx: CreateNodeContext) {
-  const { replacer } = ctx
-  const seq = new YAMLSeq(schema)
-  if (obj && Symbol.iterator in Object(obj)) {
-    let i = 0
-    for (let it of obj as Iterable<unknown>) {
-      if (typeof replacer === 'function') {
-        const key = obj instanceof Set ? it : String(i++)
-        it = replacer.call(obj, key, it)
-      }
-      seq.items.push(createNode(it, undefined, ctx))
-    }
-  }
-  return seq
-}
-
 export const seq: CollectionTag = {
   collection: 'seq',
-  createNode: createSeq,
   default: true,
   nodeClass: YAMLSeq,
   tag: 'tag:yaml.org,2002:seq',
   resolve(seq, onError) {
     if (!isSeq(seq)) onError('Expected a sequence for this tag')
     return seq
-  }
+  },
+  createNode: (schema, obj, ctx) => YAMLSeq.from(schema, obj, ctx),
 }

src/schema/types.ts

@@ -92,8 +92,14 @@ export interface CollectionTag extends TagBase {
   /**
    * The `Node` child class that implements this tag.
    * If set, used to select this tag when stringifying.
+   *
+   * If the class provides a static `from` method, then that
+   * will be used if the tag object doesn't have a `createNode` method.
    */
-  nodeClass?: new () => Node
+  nodeClass?: {
+    new (): Node
+    from?: (schema: Schema, obj: unknown, ctx: CreateNodeContext) => Node
+  }
 
   /**
    * Turns a value into an AST node.

src/schema/yaml-1.1/omap.ts

@@ -2,6 +2,8 @@ import { isPair, isScalar } from '../../nodes/identity.js'
 import { toJS, ToJSContext } from '../../nodes/toJS.js'
 import { YAMLMap } from '../../nodes/YAMLMap.js'
 import { YAMLSeq } from '../../nodes/YAMLSeq.js'
+import { CreateNodeContext } from '../../util.js'
+import type { Schema } from '../Schema.js'
 import { CollectionTag } from '../types.js'
 import { createPairs, resolvePairs } from './pairs.js'
 
@@ -41,6 +43,13 @@ export class YAMLOMap extends YAMLSeq {
     }
     return map as unknown as unknown[]
   }
+
+  static from(schema: Schema, iterable: unknown, ctx: CreateNodeContext) {
+    const pairs = createPairs(schema, iterable, ctx)
+    const omap = new this()
+    omap.items = pairs.items
+    return omap
+  }
 }
 
 export const omap: CollectionTag = {
@@ -63,12 +72,5 @@ export const omap: CollectionTag = {
       }
     }
     return Object.assign(new YAMLOMap(), pairs)
-  },
-
-  createNode(schema, iterable, ctx) {
-    const pairs = createPairs(schema, iterable, ctx)
-    const omap = new YAMLOMap()
-    omap.items = pairs.items
-    return omap
   }
 }

src/schema/yaml-1.1/set.ts

@@ -1,10 +1,11 @@
-import type { Schema } from '../../schema/Schema.js'
 import { isMap, isPair, isScalar } from '../../nodes/identity.js'
-import { createPair, Pair } from '../../nodes/Pair.js'
+import { Pair } from '../../nodes/Pair.js'
 import { Scalar } from '../../nodes/Scalar.js'
 import { ToJSContext } from '../../nodes/toJS.js'
-import { YAMLMap, findPair } from '../../nodes/YAMLMap.js'
+import { findPair, YAMLMap } from '../../nodes/YAMLMap.js'
+import type { Schema } from '../../schema/Schema.js'
 import type { StringifyContext } from '../../stringify/stringify.js'
+import { CreateNodeContext, createPair } from '../../util.js'
 import type { CollectionTag } from '../types.js'
 
 export class YAMLSet<T = unknown> extends YAMLMap<T, Scalar<null> | null> {
@@ -84,6 +85,20 @@ export class YAMLSet<T = unknown> extends YAMLMap<T, Scalar<null> | null> {
       )
     else throw new Error('Set items must all have null values')
   }
+
+  static from(schema: Schema, iterable: unknown, ctx: CreateNodeContext) {
+    const { replacer } = ctx
+    const set = new this(schema)
+    if (iterable && Symbol.iterator in Object(iterable))
+      for (let value of iterable as Iterable<unknown>) {
+        if (typeof replacer === 'function')
+          value = replacer.call(iterable, value, value)
+        set.items.push(
+          createPair(value, null, ctx) as Pair<unknown, Scalar<null>>
+        )
+      }
+    return set
+  }
 }
 
 export const set: CollectionTag = {
@@ -99,19 +114,5 @@ export const set: CollectionTag = {
       else onError('Set items must all have null values')
     } else onError('Expected a mapping for this tag')
     return map
-  },
-
-  createNode(schema, iterable, ctx) {
-    const { replacer } = ctx
-    const set = new YAMLSet(schema)
-    if (iterable && Symbol.iterator in Object(iterable))
-      for (let value of iterable as Iterable<unknown>) {
-        if (typeof replacer === 'function')
-          value = replacer.call(iterable, value, value)
-        set.items.push(
-          createPair(value, null, ctx) as Pair<unknown, Scalar<null>>
-        )
-      }
-    return set
   }
 }