UNPKG

svgo

Version:

SVGO is a Node.js library and command-line application for optimizing vector images.

267 lines (255 loc) 6.37 kB
import { visitSkip } from '../lib/util/visit.js'; import { findReferences, hasScripts } from '../lib/svgo/tools.js'; /** * @typedef CleanupIdsParams * @property {boolean=} remove * @property {boolean=} minify * @property {string[]=} preserve * @property {string[]=} preservePrefixes * @property {boolean=} force */ export const name = 'cleanupIds'; export const description = 'removes unused IDs and minifies used'; const generateIdChars = [ 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', ]; const maxIdIndex = generateIdChars.length - 1; /** * Check if an ID starts with any one of a list of strings. * * @param {string} string * @param {ReadonlyArray<string>} prefixes * @returns {boolean} */ const hasStringPrefix = (string, prefixes) => { for (const prefix of prefixes) { if (string.startsWith(prefix)) { return true; } } return false; }; /** * Generate unique minimal ID. * * @param {?number[]} currentId * @returns {number[]} */ const generateId = (currentId) => { if (currentId == null) { return [0]; } currentId[currentId.length - 1] += 1; for (let i = currentId.length - 1; i > 0; i--) { if (currentId[i] > maxIdIndex) { currentId[i] = 0; if (currentId[i - 1] !== undefined) { currentId[i - 1]++; } } } if (currentId[0] > maxIdIndex) { currentId[0] = 0; currentId.unshift(0); } return currentId; }; /** * Get string from generated ID array. * * @param {ReadonlyArray<number>} arr * @returns {string} */ const getIdString = (arr) => { return arr.map((i) => generateIdChars[i]).join(''); }; /** * Remove unused and minify used IDs (only if there are no `<style>` or * `<script>` nodes). * * @author Kir Belevich * * @type {import('../lib/types.js').Plugin<CleanupIdsParams>} */ export const fn = (_root, params) => { const { remove = true, minify = true, preserve = [], preservePrefixes = [], force = false, } = params; const preserveIds = new Set( Array.isArray(preserve) ? preserve : preserve ? [preserve] : [], ); const preserveIdPrefixes = Array.isArray(preservePrefixes) ? preservePrefixes : preservePrefixes ? [preservePrefixes] : []; /** @type {Map<string, import('../lib/types.js').XastElement>} */ const nodeById = new Map(); /** @type {Map<string, {element: import('../lib/types.js').XastElement, name: string }[]>} */ const referencesById = new Map(); let deoptimized = false; return { element: { enter: (node) => { if (!force) { // deoptimize if style or scripts are present if ( (node.name === 'style' && node.children.length !== 0) || hasScripts(node) ) { deoptimized = true; return; } // avoid removing IDs if the whole SVG consists only of defs if (node.name === 'svg') { let hasDefsOnly = true; for (const child of node.children) { if (child.type !== 'element' || child.name !== 'defs') { hasDefsOnly = false; break; } } if (hasDefsOnly) { return visitSkip; } } } for (const [name, value] of Object.entries(node.attributes)) { if (name === 'id') { // collect all ids const id = value; if (nodeById.has(id)) { delete node.attributes.id; // remove repeated id } else { nodeById.set(id, node); } } else { const ids = findReferences(name, value); for (const id of ids) { let refs = referencesById.get(id); if (refs == null) { refs = []; referencesById.set(id, refs); } refs.push({ element: node, name }); } } } }, }, root: { exit: () => { if (deoptimized) { return; } /** * @param {string} id * @returns {boolean} */ const isIdPreserved = (id) => preserveIds.has(id) || hasStringPrefix(id, preserveIdPrefixes); /** @type {?number[]} */ let currentId = null; for (const [id, refs] of referencesById) { const node = nodeById.get(id); if (node != null) { // replace referenced IDs with the minified ones if (minify && isIdPreserved(id) === false) { /** @type {?string} */ let currentIdString; do { currentId = generateId(currentId); currentIdString = getIdString(currentId); } while ( isIdPreserved(currentIdString) || (referencesById.has(currentIdString) && nodeById.get(currentIdString) == null) ); node.attributes.id = currentIdString; for (const { element, name } of refs) { const value = element.attributes[name]; if (value.includes('#')) { // replace id in href and url() element.attributes[name] = value .replace(`#${encodeURI(id)}`, `#${currentIdString}`) .replace(`#${id}`, `#${currentIdString}`); } else { // replace id in begin attribute element.attributes[name] = value.replace( `${id}.`, `${currentIdString}.`, ); } } } // keep referenced node nodeById.delete(id); } } // remove non-referenced IDs attributes from elements if (remove) { for (const [id, node] of nodeById) { if (isIdPreserved(id) === false) { delete node.attributes.id; } } } }, }, }; };