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/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
* @format
*/
'use strict';
import type {IndexMap, IndexMapSection, MixedSourceMap} from './source-map';
const EMPTY_MAP = {
version: 3,
sources: [],
names: [],
mappings: 'A',
};
/**
* Builds a source-mapped bundle by concatenating strings and their
* corresponding source maps (if any).
*
* Usage:
*
* const builder = new BundleBuilder('bundle.js');
* builder
* .append('foo\n', fooMap)
* .append('bar\n')
* // ...
* const code = builder.getCode();
* const map = builder.getMap();
*/
class BundleBuilder {
_file: string;
_sections: Array<IndexMapSection>;
_line: number;
_column: number;
_code: string;
_afterMappedContent: boolean;
constructor(file: string) {
this._file = file;
this._sections = [];
this._line = 0;
this._column = 0;
this._code = '';
this._afterMappedContent = false;
}
_pushMapSection(map: MixedSourceMap) {
this._sections.push({
map,
offset: {column: this._column, line: this._line},
});
}
_endMappedContent() {
if (this._afterMappedContent) {
this._pushMapSection(EMPTY_MAP);
this._afterMappedContent = false;
}
}
append(code: string, map: ?MixedSourceMap): this {
if (!code.length) {
return this;
}
const {lineBreaks, lastLineColumns} = measureString(code);
if (map) {
this._pushMapSection(map);
this._afterMappedContent = true;
} else {
this._endMappedContent();
}
this._afterMappedContent = !!map;
this._line = this._line + lineBreaks;
if (lineBreaks > 0) {
this._column = lastLineColumns;
} else {
this._column = this._column + lastLineColumns;
}
this._code = this._code + code;
return this;
}
getMap(): MixedSourceMap {
this._endMappedContent();
return createIndexMap(this._file, this._sections);
}
getCode(): string {
return this._code;
}
}
const reLineBreak = /\r\n|\r|\n/g;
function measureString(str: string): {
lineBreaks: number,
lastLineColumns: number,
} {
let lineBreaks = 0;
let match;
let lastLineStart = 0;
while ((match = reLineBreak.exec(str))) {
++lineBreaks;
lastLineStart = match.index + match[0].length;
}
const lastLineColumns = str.length - lastLineStart;
return {lineBreaks, lastLineColumns};
}
function createIndexMap(
file: string,
sections: Array<IndexMapSection>,
): IndexMap {
return {
version: 3,
file,
sections,
};
}
module.exports = {BundleBuilder, createIndexMap};