refactor: implement let tag

fixtures/let-tag-array-destructure/compiled.js

@@ -0,0 +1,13 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+let [username, age] = state.user;
+$lineNumber = 2;
+out += `${template.escape(username)}`;
+out += ", ";
+out += `${template.escape(age)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag-array-destructure/index.edge

@@ -0,0 +1,2 @@
+@let([username, age] = user)
+{{ username }}, {{ age }}

fixtures/let-tag-array-destructure/index.json

@@ -0,0 +1,3 @@
+{
+  "user": ["virk", 32]
+}

fixtures/let-tag-array-destructure/index.txt

@@ -0,0 +1 @@
+virk, 32

fixtures/let-tag-destructure-array-spread/compiled.js

@@ -0,0 +1,15 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+let [username, age, ...rest] = state.user;
+$lineNumber = 2;
+out += `${template.escape(username)}`;
+out += ", ";
+out += `${template.escape(age)}`;
+out += " ";
+out += `${template.escape(rest)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag-destructure-array-spread/index.edge

@@ -0,0 +1,2 @@
+@let([username, age, ...rest] = user)
+{{ username }}, {{ age }} {{ rest }}

fixtures/let-tag-destructure-array-spread/index.json

@@ -0,0 +1,3 @@
+{
+  "user": ["virk", 32]
+}

fixtures/let-tag-destructure-array-spread/index.txt

@@ -0,0 +1 @@
+virk, 32

fixtures/let-tag-destructure-reassign/compiled.js

@@ -0,0 +1,13 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+let {username, age: userAge} = state.user;
+$lineNumber = 2;
+out += `${template.escape(username)}`;
+out += ", ";
+out += `${template.escape(userAge)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag-destructure-reassign/index.edge

@@ -0,0 +1,2 @@
+@let({ username, age: userAge } = user)
+{{ username }}, {{ userAge }}

fixtures/let-tag-destructure-reassign/index.json

@@ -0,0 +1,6 @@
+{
+  "user": {
+    "username": "virk",
+    "age": 32
+  }
+}

fixtures/let-tag-destructure-reassign/index.txt

@@ -0,0 +1 @@
+virk, 32

fixtures/let-tag-destructure-spread/compiled.js

@@ -0,0 +1,15 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+let {username, age, ...rest} = state.user;
+$lineNumber = 2;
+out += `${template.escape(username)}`;
+out += ", ";
+out += `${template.escape(age)}`;
+out += " ";
+out += `${template.escape(rest)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag-destructure-spread/index.edge

@@ -0,0 +1,2 @@
+@let({ username, age, ...rest } = user)
+{{ username }}, {{ age }} {{ rest }}

fixtures/let-tag-destructure-spread/index.json

@@ -0,0 +1,6 @@
+{
+  "user": {
+    "username": "virk",
+    "age": 32
+  }
+}

fixtures/let-tag-destructure-spread/index.txt

@@ -0,0 +1 @@
+virk, 32 [object Object]

fixtures/let-tag-destructure/compiled.js

@@ -0,0 +1,13 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+let {username, age} = state.user;
+$lineNumber = 2;
+out += `${template.escape(username)}`;
+out += ", ";
+out += `${template.escape(age)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag-destructure/index.edge

@@ -0,0 +1,2 @@
+@let({ username, age } = user)
+{{ username }}, {{ age }}

fixtures/let-tag-destructure/index.json

@@ -0,0 +1,6 @@
+{
+  "user": {
+    "username": "virk",
+    "age": 32
+  }
+}

fixtures/let-tag-destructure/index.txt

@@ -0,0 +1 @@
+virk, 32

fixtures/let-tag-scope/compiled.js

@@ -0,0 +1,24 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+template.loop(state.users, function (user) {
+out += "\n";
+$lineNumber = 2;
+let index = 0;
+$lineNumber = 3;
+index = index + 1;
+out += "  ";
+$lineNumber = 4;
+out += `${template.escape(index)}`;
+});
+$lineNumber = 6;
+state.index = (state.index || 0) + 1;
+out += "";
+out += "\n";
+$lineNumber = 8;
+out += `${template.escape(state.index)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag-scope/index.edge

@@ -0,0 +1,8 @@
+@each(user in users)
+  @let(index = 0)
+  @eval(index = index + 1)
+  {{ index }}
+@end
+@eval(index = (index || 0) + 1)
+
+{{ index }}

fixtures/let-tag-scope/index.json

@@ -0,0 +1,3 @@
+{
+  "users": ["virk"]
+}

fixtures/let-tag-scope/index.txt

@@ -0,0 +1,2 @@
+1
+1

fixtures/let-tag/compiled.js

@@ -0,0 +1,11 @@
+let out = "";
+let $lineNumber = 1;
+let $filename = "{{__dirname}}index.edge";
+try {
+let username = 'nikk';
+$lineNumber = 2;
+out += `${template.escape(username)}`;
+} catch (error) {
+template.reThrow(error, $filename, $lineNumber);
+}
+return out;

fixtures/let-tag/index.edge

@@ -0,0 +1,2 @@
+@let(username = 'nikk')
+{{ username }}

fixtures/set-tag-compat/index.txt

@@ -0,0 +1 @@
+nikk

fixtures/set-tag-update-value-compat/index.json

@@ -0,0 +1,3 @@
+{
+  "username": "virk"
+}

src/tags/let.ts

@@ -0,0 +1,86 @@
+/*
+ * edge.js
+ *
+ * (c) EdgeJS
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+import { EdgeError } from 'edge-error'
+import { expressions } from 'edge-parser'
+import lodash from '@poppinss/utils/lodash'
+
+import { TagContract } from '../types.js'
+import { isSubsetOf, unallowedExpression, parseJsArg } from '../utils.js'
+
+/**
+ * The let tag is used to set runtime values within the template. The value
+ * is set inside the current scope of the template.
+ */
+export const letTag: TagContract = {
+  block: false,
+  seekable: true,
+  tagName: 'let',
+  noNewLine: true,
+
+  /**
+   * Compiles else block node to Javascript else statement
+   */
+  compile(parser, buffer, token) {
+    const parsed = parser.utils.generateAST(
+      `let ${token.properties.jsArg}`,
+      token.loc,
+      token.filename
+    ).declarations[0]
+
+    const key = parsed.id
+    const value = parsed.init
+
+    /**
+     * The variable name has to be an identifier or the destructuring
+     * operator.
+     */
+    isSubsetOf(key, ['ObjectPattern', expressions.Identifier, 'ArrayPattern'], () => {
+      throw unallowedExpression(
+        `Invalid variable name for the @let tag`,
+        token.filename,
+        parser.utils.getExpressionLoc(key)
+      )
+    })
+
+    /**
+     * Define local variables based upon the expression
+     */
+    if (key.type === 'Identifier') {
+      parser.stack.defineVariable(key.name)
+    } else if (key.type === 'ObjectPattern') {
+      key.properties.forEach((property: any) => {
+        parser.stack.defineVariable(
+          property.argument ? property.argument.name : property.value.name
+        )
+      })
+    } else if (key.type === 'ArrayPattern') {
+      key.elements.forEach((element: any) => {
+        parser.stack.defineVariable(element.argument ? element.argument.name : element.name)
+      })
+    }
+
+    /**
+     * Declare let variable
+     */
+    const expression = `let ${parser.utils.stringify(key)} = ${parser.utils.stringify(
+      parser.utils.transformAst(value, token.filename, parser)
+    )}`
+
+    buffer.writeExpression(expression, token.filename, token.loc.start.line)
+    parser.stack.defineVariable(key.value)
+  },
+
+  /**
+   * Add methods to the template for running the loop
+   */
+  boot(template) {
+    template.macro('setValue', lodash.set)
+  },
+}

src/tags/main.ts

@@ -8,6 +8,7 @@
  */
 
 export { ifTag as if } from './if.js'
+export { letTag as let } from './let.js'
 export { eachTag as each } from './each.js'
 export { slotTag as slot } from './slot.js'
 export { elseTag as else } from './else.js'

src/utils.ts

@@ -13,7 +13,7 @@ import type { TagToken } from 'edge-lexer/types'
 import { find, html } from 'property-information'
 import { expressions as expressionsList, Parser } from 'edge-parser'
 
-type ExpressionList = readonly (keyof typeof expressionsList)[]
+type ExpressionList = readonly (keyof typeof expressionsList | 'ObjectPattern' | 'ArrayPattern')[]
 
 /**
  * Function to register custom properties