packages/babel-generator/src/source-map.js
import sourceMap from "source-map";
/**
* Build a sourcemap.
*/
export default class SourceMap {
constructor(opts, code) {
this._cachedMap = null;
this._code = code;
this._opts = opts;
this._rawMappings = [];
}
/**
* Get the sourcemap.
*/
get() {
if (!this._cachedMap) {
const map = (this._cachedMap = new sourceMap.SourceMapGenerator({
sourceRoot: this._opts.sourceRoot,
}));
const code = this._code;
if (typeof code === "string") {
map.setSourceContent(
this._opts.sourceFileName.replace(/\\/g, "/"),
code,
);
} else if (typeof code === "object") {
Object.keys(code).forEach(sourceFileName => {
map.setSourceContent(
sourceFileName.replace(/\\/g, "/"),
code[sourceFileName],
);
});
}
this._rawMappings.forEach(mapping => map.addMapping(mapping), map);
}
return this._cachedMap.toJSON();
}
getRawMappings() {
return this._rawMappings.slice();
}
/**
* Mark the current generated position with a source position. May also be passed null line/column
* values to insert a mapping to nothing.
*/
mark(
generatedLine: number,
generatedColumn: number,
line: number,
column: number,
identifierName: ?string,
filename: ?string,
force?: boolean,
) {
// Adding an empty mapping at the start of a generated line just clutters the map.
if (this._lastGenLine !== generatedLine && line === null) return;
// If this mapping points to the same source location as the last one, we can ignore it since
// the previous one covers it.
if (
!force &&
this._lastGenLine === generatedLine &&
this._lastSourceLine === line &&
this._lastSourceColumn === column
) {
return;
}
this._cachedMap = null;
this._lastGenLine = generatedLine;
this._lastSourceLine = line;
this._lastSourceColumn = column;
// We are deliberately not using the `source-map` library here to allow
// callers to use these mappings without any overhead
this._rawMappings.push({
// undefined to allow for more compact json serialization
name: identifierName || undefined,
generated: {
line: generatedLine,
column: generatedColumn,
},
source:
line == null
? undefined
: (filename || this._opts.sourceFileName).replace(/\\/g, "/"),
original:
line == null
? undefined
: {
line: line,
column: column,
},
});
}
}