@putout/engine-parser

@putout/engine-parser

🐊Putout engine that parses input.

Install

npm i @putout/engine-parser

Supported parsers

• @babel/parse
• acorn
• espree
• esprima
• tenko

Any parser should be installed before use, but you can be sure that @babel/parse always installed.

API

By default @putout/printer used. It formats code according to eslint-plugin-putout rules but without using ESLint.

But you can also use babel with:

const ast = parse(source);
const code = print(ast, {
    printer: 'babel',
});

When you need to pass options, use:

const code = print(ast, {
    printer: ['putout', {
        format: {
            indent: '    ',
        },
    }],
});

print(ast, {
    printer: ['babel', {
        alginSpaces: false, // when you don't want to add spaces on empty lines
    }],
});

print(ast [, options])

Print code from ast

parse(code, [, options])

You can add default options for custom parser you use.

template.fresh(code)

parse without memoization.

template.ast(code)

create node using memoization.

template.ast.fresh(code)

create node without memoization.

template.extractExpression(code)

Extract expression node from ExpressionStatement.

Generate sourcemaps using Babel

To generate sourcemap using babel generator, you should use babel parser before. This is low level transformation, because Babel doesn't preserve any formatting.

const {generate} = require('@putout/engine-parser');
const {parse} = require('@putout/engine-parser/babel');

const ast = parse(source, {
    sourceFilename: 'hello.js',
});

generate(ast, {sourceMaps: true}, {
    'hello.js': source,
});

// returns
({
    code,
    map,
});

Example

const {parse} = require('@putout/engine-parser');
const parser = 'acorn';

const code = parse('var t = "hello"', {
    parser,
});

License

MIT