feat(tags): add set tag

set tag allows data mutation at runtime with templates

src/Tags/SetTag.js

@@ -0,0 +1,89 @@
+'use strict'
+
+/*
+ * edge
+ *
+ * (c) Harminder Virk <virk@adonisjs.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+*/
+
+const BaseTag = require('./BaseTag')
+const _ = require('lodash')
+
+/**
+ * The `set` tag allows you to mutate data
+ * object for a given template.
+ *
+ * @class SetTag
+ * @extends {BaseTag}
+ * @static
+ */
+class SetTag extends BaseTag {
+  /**
+   * Tag name to be used for registering
+   * the tag
+   *
+   * @method tagName
+   *
+   * @return {String}
+   */
+  get tagName () {
+    return 'set'
+  }
+
+  /**
+   * Whether or not the tag is block level
+   * tag. Which is no in this case.
+   *
+   * @method isBlock
+   *
+   * @return {Boolean}
+   */
+  get isBlock () {
+    return false
+  }
+
+  /**
+   * The expressions allowed inside an if tag.
+   *
+   * @method allowedExpressions
+   *
+   * @return {Array}
+   */
+  get allowedExpressions () {
+    return ['SequenceExpression']
+  }
+
+  /**
+   * Compile the template
+   *
+   * @method compile
+   *
+   * @param  {Object} compiler
+   * @param  {Object} lexer
+   * @param  {Object} buffer
+   * @param  {String} options.body
+   * @param  {Array}  options.childs
+   * @param  {Number} options.lineno
+   *
+   * @return {void}
+   */
+  compile (compiler, lexer, buffer, { body, childs, lineno }) {
+    const [lhs, rhs] = this._compileStatement(lexer, body, lineno).toStatement()
+    buffer.writeLine(`this.context.setValue(${lhs}, ${rhs})`)
+  }
+
+  /**
+   * Nothing needs to be done in runtime
+   * for an include tag
+   */
+  run (Context) {
+    Context.macro('setValue', function (key, value) {
+      _.set(this.$presenter.$data, key, value)
+    })
+  }
+}
+
+module.exports = SetTag

src/Tags/index.js

@@ -22,5 +22,6 @@ module.exports = {
   debugger: new (require('./DebuggerTag'))(),
   raw: new (require('./RawTag'))(),
   unless: new (require('./UnlessTag'))(),
-  mustache: new (require('./MustacheTag'))()
+  mustache: new (require('./MustacheTag'))(),
+  set: new (require('./SetTag'))()
 }

test/unit/tags/set.spec.js

@@ -0,0 +1,120 @@
+'use strict'
+
+/*
+ * edge
+ *
+ * (c) Harminder Virk <virk@adonisjs.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+*/
+
+const test = require('japa')
+const Template = require('../../../src/Template')
+const Loader = require('../../../src/Loader')
+const Context = require('../../../src/Context')
+const dedent = require('dedent-js')
+const path = require('path')
+const loader = new Loader(path.join(__dirname, '../../../test-helpers/views'))
+
+test.group('Tags | Set ', (group) => {
+  group.beforeEach(() => {
+    require('../../../test-helpers/transform-tags')(this, require('../../../src/Tags'))
+  })
+
+  test('parse the set block which mutates the data', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('username', 'virk')
+    `
+    const output = template.compileString(statement)
+
+    assert.equal(output, dedent`
+    return (function templateFn () {
+      let out = new String()
+      this.context.setValue('username', 'virk')
+      return out
+    }).bind(this)()
+    `)
+  })
+
+  test('parse the set block with value as an array of data', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('users', ['virk'])
+    `
+    const output = template.compileString(statement)
+
+    assert.equal(output, dedent`
+    return (function templateFn () {
+      let out = new String()
+      this.context.setValue('users', ['virk'])
+      return out
+    }).bind(this)()
+    `)
+  })
+
+  test('parse the set block with value as a reference', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('users', admin.users)
+    `
+    const output = template.compileString(statement)
+
+    assert.equal(output, dedent`
+    return (function templateFn () {
+      let out = new String()
+      this.context.setValue('users', this.context.accessChild(this.context.resolve('admin'), ['users']))
+      return out
+    }).bind(this)()
+    `)
+  })
+
+  test('set literal value at runtime', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('username', 'virk')
+    {{ username }}
+    `
+
+    this.tags.set.run(Context)
+    const output = template.renderString(statement)
+    assert.equal(output.trim(), 'virk')
+  })
+
+  test('set identifier at runtime', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('username', admin.username)
+    {{ username }}
+    `
+
+    this.tags.set.run(Context)
+    const output = template.renderString(statement, { admin: { username: 'virk' } })
+    assert.equal(output.trim(), 'virk')
+  })
+
+  test('set array at runtime', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('users', ['virk', 'nikk'])
+    {{ users.join(',') }}
+    `
+
+    this.tags.set.run(Context)
+    const output = template.renderString(statement)
+    assert.equal(output.trim(), 'virk,nikk')
+  })
+
+  test('set array at runtime', (assert) => {
+    const template = new Template(this.tags, {}, {}, loader)
+    const statement = dedent`
+    @set('users', ['virk', 'nikk'])
+    {{ users.join(',') }}
+    `
+
+    this.tags.set.run(Context)
+    const output = template.renderString(statement)
+    assert.equal(output.trim(), 'virk,nikk')
+  })
+})