webpack/lib/logging/truncateArgs.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const arraySum = array => {
	let sum = 0;
	for (const item of array) sum += item;
	return sum;
};

/**
 * @param {any[]} args items to be truncated
 * @param {number} maxLength maximum length of args including spaces between
 * @returns {string[]} truncated args
 */
const truncateArgs = (args, maxLength) => {
	const lengths = args.map(a => `${a}`.length);
	const availableLength = maxLength - lengths.length + 1;

	if (availableLength > 0 && args.length === 1) {
		if (availableLength >= args[0].length) {
			return args;
		} else if (availableLength > 3) {
			return ["..." + args[0].slice(-availableLength + 3)];
		} else {
			return [args[0].slice(-availableLength)];
		}
	}

	// Check if there is space for at least 4 chars per arg
	if (availableLength < arraySum(lengths.map(i => Math.min(i, 6)))) {
		// remove args
		if (args.length > 1)
			return truncateArgs(args.slice(0, args.length - 1), maxLength);
		return [];
	}

	let currentLength = arraySum(lengths);

	// Check if all fits into maxLength
	if (currentLength <= availableLength) return args;

	// Try to remove chars from the longest items until it fits
	while (currentLength > availableLength) {
		const maxLength = Math.max(...lengths);
		const shorterItems = lengths.filter(l => l !== maxLength);
		const nextToMaxLength =
			shorterItems.length > 0 ? Math.max(...shorterItems) : 0;
		const maxReduce = maxLength - nextToMaxLength;
		let maxItems = lengths.length - shorterItems.length;
		let overrun = currentLength - availableLength;
		for (let i = 0; i < lengths.length; i++) {
			if (lengths[i] === maxLength) {
				const reduce = Math.min(Math.floor(overrun / maxItems), maxReduce);
				lengths[i] -= reduce;
				currentLength -= reduce;
				overrun -= reduce;
				maxItems--;
			}
		}
	}

	// Return args reduced to length in lengths
	return args.map((a, i) => {
		const str = `${a}`;
		const length = lengths[i];
		if (str.length === length) {
			return str;
		} else if (length > 5) {
			return "..." + str.slice(-length + 3);
		} else if (length > 0) {
			return str.slice(-length);
		} else {
			return "";
		}
	});
};

module.exports = truncateArgs;