Mappings.js

const wordRegex = /\w/;

export default class Mappings {
	constructor(hires) {
		this.hires = hires;
		this.generatedCodeLine = 0;
		this.generatedCodeColumn = 0;
		this.raw = [];
		this.rawSegments = this.raw[this.generatedCodeLine] = [];
		this.pending = null;
	}

	addEdit(sourceIndex, content, loc, nameIndex) {
		if (content.length) {
			const contentLengthMinusOne = content.length - 1;
			let contentLineEnd = content.indexOf('\n', 0);
			let previousContentLineEnd = -1;
			// Loop through each line in the content and add a segment, but stop if the last line is empty,
			// else code afterwards would fill one line too many
			while (contentLineEnd >= 0 && contentLengthMinusOne > contentLineEnd) {
				const segment = [this.generatedCodeColumn, sourceIndex, loc.line, loc.column];
				if (nameIndex >= 0) {
					segment.push(nameIndex);
				}
				this.rawSegments.push(segment);

				this.generatedCodeLine += 1;
				this.raw[this.generatedCodeLine] = this.rawSegments = [];
				this.generatedCodeColumn = 0;

				previousContentLineEnd = contentLineEnd;
				contentLineEnd = content.indexOf('\n', contentLineEnd + 1);
			}

			const segment = [this.generatedCodeColumn, sourceIndex, loc.line, loc.column];
			if (nameIndex >= 0) {
				segment.push(nameIndex);
			}
			this.rawSegments.push(segment);

			this.advance(content.slice(previousContentLineEnd + 1));
		} else if (this.pending) {
			this.rawSegments.push(this.pending);
			this.advance(content);
		}

		this.pending = null;
	}

	addUneditedChunk(sourceIndex, chunk, original, loc, sourcemapLocations) {
		let originalCharIndex = chunk.start;
		let first = true;
		// when iterating each char, check if it's in a word boundary
		let charInHiresBoundary = false;

		while (originalCharIndex < chunk.end) {
			if (this.hires || first || sourcemapLocations.has(originalCharIndex)) {
				const segment = [this.generatedCodeColumn, sourceIndex, loc.line, loc.column];

				if (this.hires === 'boundary') {
					// in hires "boundary", group segments per word boundary than per char
					if (wordRegex.test(original[originalCharIndex])) {
						// for first char in the boundary found, start the boundary by pushing a segment
						if (!charInHiresBoundary) {
							this.rawSegments.push(segment);
							charInHiresBoundary = true;
						}
					} else {
						// for non-word char, end the boundary by pushing a segment
						this.rawSegments.push(segment);
						charInHiresBoundary = false;
					}
				} else {
					this.rawSegments.push(segment);
				}
			}

			if (original[originalCharIndex] === '\n') {
				loc.line += 1;
				loc.column = 0;
				this.generatedCodeLine += 1;
				this.raw[this.generatedCodeLine] = this.rawSegments = [];
				this.generatedCodeColumn = 0;
				first = true;
			} else {
				loc.column += 1;
				this.generatedCodeColumn += 1;
				first = false;
			}

			originalCharIndex += 1;
		}

		this.pending = null;
	}

	advance(str) {
		if (!str) return;

		const lines = str.split('\n');

		if (lines.length > 1) {
			for (let i = 0; i < lines.length - 1; i++) {
				this.generatedCodeLine++;
				this.raw[this.generatedCodeLine] = this.rawSegments = [];
			}
			this.generatedCodeColumn = 0;
		}

		this.generatedCodeColumn += lines[lines.length - 1].length;
	}
}