diff --git a/packages/babel-generator/README.md b/packages/babel-generator/README.md index 0164d55c2e..ef4909834e 100644 --- a/packages/babel-generator/README.md +++ b/packages/babel-generator/README.md @@ -44,4 +44,47 @@ 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) +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 make some changes to your code. + +First, each node with a `loc` property (which indicates that node's original placement in the +source document) must also include a `loc.filename` property, set to the source filename. + +Second, you should 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 traverse from "babel-traverse"; +import generate from 'babel-generator'; + +function addFilename (ast, filename) { + traverse.cheap(ast, node => { + if (node.loc) { node.loc.source = sourcePath }; + }); +} + +const a = 'var a = 1;'; +const b = 'var b = 2;'; +const astA = addFilename(parse(a), 'a.js'); +const astB = addFilename(parse(b), 'b.js'); +const ast = { + type: 'Program', + body: [].concat(astA.body, ast2.body) +}; + +const { code, map } = generate(ast, { /* options */ }, { + 'a.js': a, + 'b.js': b +}); + +// Sourcemap will point to both a.js and b.js where appropriate. +``` diff --git a/packages/babel-generator/src/source-map.js b/packages/babel-generator/src/source-map.js index 6213873ad7..beea55bddf 100644 --- a/packages/babel-generator/src/source-map.js +++ b/packages/babel-generator/src/source-map.js @@ -17,7 +17,13 @@ export default class SourceMap { sourceRoot: opts.sourceRoot }); - this.map.setSourceContent(opts.sourceFileName, code); + if (typeof code === "string") { + this.map.setSourceContent(opts.sourceFileName, code); + } else if (typeof code === "object") { + Object.keys(code).forEach((sourceFileName) => { + this.map.setSourceContent(sourceFileName, code[sourceFileName]); + }); + } } else { this.map = null; }