babel-generator

> Turns an AST into code.

Install

``sh
npm install --save-dev babel-generator
`

Usage

`js
import {parse} from 'babylon';
import generate from 'babel-generator';

const code = 'class Example {}';
const ast = parse(code);

const output = generate(ast, { / options / }, code);
`

Options

Options for formatting output:

name | type | default | description
-----------------------|----------|-----------------|--------------------------------------------------------------------------
auxiliaryCommentBefore | string | | Optional string to add as a block comment at the start of the output file
auxiliaryCommentAfter | string | | Optional string to add as a block comment at the end of the output file
shouldPrintComment | function | opts.comments | Function that takes a comment (as a string) and returns true if the comment should be included in the output. By default, comments are included if opts.comments is true or if opts.minifed is false and the comment contains @preserve or @license
retainLines | boolean | false | Attempt to use the same line numbers in the output code as in the source code (helps preserve stack traces)
retainFunctionParens | boolean | false | Retain parens around function expressions (could be used to change engine parsing behavior)
comments | boolean | true | Should comments be included in output
compact | boolean or 'auto' | opts.minified | Set to true to avoid adding whitespace for formatting
minified | boolean | false | Should the output be minified
concise | boolean | false | Set to true to reduce whitespace (but not as much as opts.compact)
quotes | 'single' or 'double' | autodetect based on ast.tokens | The type of quote to use in the output
filename | string | | Used in warning messages
flowCommaSeparator | boolean | false | Set to true to use commas instead of semicolons as Flow property separators
jsonCompatibleStrings | boolean | false | Set to true to run jsesc with "json": true to print "\u00A9" vs. "©";

Options for source maps:

name | type | default | description
-----------------------|----------|-----------------|--------------------------------------------------------------------------
sourceMaps | boolean | false | Enable generating source maps
sourceMapTarget | string | | The filename of the generated code that the source map will be associated with
sourceRoot | string | | A root for all relative URLs in the source map
sourceFileName | string | | The filename for the source code (i.e. the code in the code argument). This will only be used if code is a string.

AST from Multiple Sources

In most cases, Babel does a 1:1 transformation of input-file to output-file. However,
you may be dealing with AST constructed from multiple sources - JS files, templates, etc.
If this is the case, and you want the sourcemaps to reflect the correct sources, you'll need
to pass an object to generate as the code parameter. Keys
should be the source filenames, and values should be the source content.

Here's an example of what that might look like:

`js
import {parse} from 'babylon';
import generate from 'babel-generator';

const a = 'var a = 1;';
const b = 'var b = 2;';
const astA = parse(a, { sourceFilename: 'a.js' });
const astB = parse(b, { sourceFilename: 'b.js' });
const ast = {
type: 'Program',
body: [].concat(astA.program.body, astB.program.body)
};

const { code, map } = generate(ast, { sourceMaps: true }, {
'a.js': a,
'b.js': b
});

// Sourcemap will point to both a.js and b.js where appropriate.
``