babel-template

What is babel-template?

The babel-template npm package is a utility that allows developers to create reusable AST (Abstract Syntax Tree) templates based on a string input. It simplifies the process of generating AST nodes programmatically, which is particularly useful when working with Babel plugins that manipulate code.

What are babel-template's main functionalities?

AST Template Creation

This feature allows the creation of AST nodes from a template string. The example shows how to create a variable declaration that requires a module, with placeholders for the module name and source.

const template = require('babel-template');
const buildRequire = template(`
  var IMPORT_NAME = require(SOURCE);
`);
const ast = buildRequire({
  IMPORT_NAME: 'myModule',
  SOURCE: '"my-module"'
});

Other packages similar to babel-template

@babel/template

This package is an official part of the Babel ecosystem and serves a similar purpose to babel-template, providing API improvements and better integration with the latest Babel versions. It offers enhanced usability and security features.

recast

Recast is another tool for manipulating ASTs. It focuses on preserving the original formatting as much as possible, which is different from babel-template's approach of creating new AST nodes from templates. Recast is better suited for applications where code formatting needs to be maintained.

README

babel-template

Generate an AST from a string template.

In computer science, this is known as an implementation of quasiquotes.

Install

npm install --save-dev babel-template

Usage

import template from 'babel-template';
import generate from 'babel-generator';
import * as t from 'babel-types';

const buildRequire = template(`
  var IMPORT_NAME = require(SOURCE);
`);

const ast = buildRequire({
  IMPORT_NAME: t.identifier('myModule'),
  SOURCE: t.stringLiteral('my-module')
});

console.log(generate(ast).code);

var myModule = require('my-module');

API

template(code, [opts])

code

Type: string

options

babel-template accepts all of the options from babylon, and specifies some defaults of its own:

• allowReturnOutsideFunction is set to true by default.
• allowSuperOutsideMethod is set to true by default.

preserveComments

Type: boolean Default: false

Set this to true to preserve any comments from the code parameter.

Return value

babel-template returns a function which is invoked with an optional object of replacements. See the usage section for an example.