[REFACTOR] Replace `getLocFromIndex` and `getIndexFromLoc` methods with ESLint's native APIs

[lumirlumir]

Hi @yeonjuan — I came here from ESLint. 😄

A new feature adding native support for getLocFromIndex and getIndexFromLoc was merged in eslint/rewrite#212, so those methods can be replaced with the native API.

Current implementation:

html-eslint/packages/eslint-plugin/lib/languages/html-source-code.js

Lines 80 to 156 in 0a2e241

	getIndexFromLoc(loc) {
	if (
	typeof loc !== "object" ||
	typeof loc.line !== "number" ||
	typeof loc.column !== "number"
	) {
	throw new TypeError(
	"Expected `loc` to be an object with numeric `line` and `column` properties."
	);
	}
	if (loc.line <= 0) {
	throw new RangeError(
	`Line number out of range (line ${loc.line} requested). Line numbers should be 1-based.`
	);
	}
	if (loc.line > this.lineStartIndices.length) {
	throw new RangeError(
	`Line number out of range (line ${loc.line} requested, but only ${this.lineStartIndices.length} lines present).`
	);
	}
	const lineStartIndex = this.lineStartIndices[loc.line - 1];
	const lineEndIndex =
	loc.line === this.lineStartIndices.length
	? this.text.length
	: this.lineStartIndices[loc.line];
	const positionIndex = lineStartIndex + loc.column;
	if (
	(loc.line === this.lineStartIndices.length &&
	positionIndex > lineEndIndex) ||
	(loc.line < this.lineStartIndices.length && positionIndex >= lineEndIndex)
	) {
	throw new RangeError(
	`Column number out of range (column ${loc.column} requested, but the length of line ${loc.line} is ${lineEndIndex - lineStartIndex}).`
	);
	}
	return positionIndex;
	}
	// Copied from eslint source code
	/**
	* @see https://github.com/eslint/eslint/blob/f60f2764971a33e252be13e560dccf21f554dbf1/lib/languages/js/source-code/source-code.js#L694
	* @param {number} index
	* @returns {Position}
	*/
	getLocFromIndex(index) {
	if (typeof index !== "number") {
	throw new TypeError("Expected `index` to be a number.");
	}
	if (index < 0 || index > this.text.length) {
	throw new RangeError(
	`Index out of range (requested index ${index}, but source text has length ${this.text.length}).`
	);
	}
	if (index === this.text.length) {
	return {
	line: this.lines.length,
	// @ts-ignore
	column: this.lines.at(-1).length,
	};
	}
	const lineNumber =
	// @ts-ignore
	index >= this.lineStartIndices.at(-1)
	? this.lineStartIndices.length
	: this.lineStartIndices.findIndex((el) => index < el);
	return {
	line: lineNumber,
	column: index - this.lineStartIndices[lineNumber - 1],
	};
	}

It’s pending release and will be available after @eslint/plugin-kit 0.4.0 is published.

The native API is faster thanks to a more efficient lookup algorithm and lazy calculation, which reduces memory usage and improves performance.

Please feel free to take a look at it!

[yeonjuan]

@lumirlumir That's great! Thank you for sharing.