@salesforce/acorn-visualforce

Acorn-VisualForce

This is plugin for Acorn - a tiny, fast JavaScript parser, written completely in JavaScript.

It was created as an experimental parser for VisualForce inline JS.

Usage

You can use module directly in order to get Acorn instance with plugin installed:

const acorn = require('@salesforce/acorn-visualforce');

Or you can use inject.js for injecting plugin into your own version of Acorn like following:

const acorn = require('@salesforce/acorn-visualforce/dist/inject')(require('./custom-acorn'));

Then, use plugins option whenever you need to support VisualForce merge fields while parsing:

const code = 'var foo = {! JSENCODE(someApexVariable) };'
const ast = acorn.parse(code, {
  plugins: {
    jsx: true, // make sure that jsx appears BEFORE vfel to work correctly
    vfel: true,
  }
});

Produces:

{
    "type": "Program",
    "start": 0,
    "end": 42,
    "body": [{
        "type": "VariableDeclaration",
        "start": 0,
        "end": 42,
        "declarations": [{
            "type": "VariableDeclarator",
            "start": 4,
            "end": 41,
            "id": {
                "type": "Identifier",
                "start": 4,
                "end": 7,
                "name": "foo"
            },
            "init": {
                "type": "VFELExpression",
                "start": 10,
                "end": 41,
                "value": {
                    "type": "CallExpression",
                    "start": 12,
                    "end": 39,
                    "callee": {
                        "type": "Identifier",
                        "start": 12,
                        "end": 21,
                        "name": "JSENCODE"
                    },
                    "arguments": [{
                        "type": "Identifier",
                        "start": 22,
                        "end": 38,
                        "name": "someApexVariable"
                    }]
                }
            }
        }],
        "kind": "var"
    }],
    "sourceType": "script"
}

The injector function also supports an optional second parameter that allows to force-inject the plugin, so that there is no need to specify the plugins options to parse or tokenize functions. This is useful for monkey-patching other parser wrappers such as espree that force their own plugin options.

const acorn = require('@salesforce/acorn-visualforce/dist/inject')(require('./custom-acorn'), true);
const code = 'var foo = {! JSENCODE(someApexVariable) };'
const ast = acorn.parse(code);

License

This plugin is issued under the BSD-3-Clause license.