Install
sh
npm install --save-dev @babel/generator
Usage
js
import {parse} from '@babel/parser';
import generate from '@babel/generator';
const code = 'class Example {}';
const ast = parse(code);
const output = generate(ast, { /* options */ }, code);
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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) |
filename | string | Used in warning messages | |
jsonCompatibleStrings | boolean | false | Set to true to run jsesc with "json": true to print "\u00A9" vs. "©"; |
Js中文网 – 前端进阶资源教程 www.javascriptC.com ,Babel中文文档
一个致力于帮助开发者用代码改变世界为使命的平台
Options for source maps:
name | type | default | description |
---|---|---|---|
sourceMaps | boolean | false | Enable generating source maps |
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 '@babel/parser';
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.
来源:Js中文网 – 前端进阶资源教程
链接:https://www.javascriptc.com/docs/babel-manual/babel-generator