import { List, clone, walk } from 'css-tree'; import { buildIndex } from './usage.js'; import clean from './clean/index.js'; import replace from './replace/index.js'; import restructure from './restructure/index.js'; function readChunk(input, specialComments) { const children = new List(); let nonSpaceTokenInBuffer = false; let protectedComment; input.nextUntil(input.head, (node, item, list) => { if (node.type === 'Comment') { if (!specialComments || node.value.charAt(0) !== '!') { list.remove(item); return; } if (nonSpaceTokenInBuffer || protectedComment) { return true; } list.remove(item); protectedComment = node; return; } if (node.type !== 'WhiteSpace') { nonSpaceTokenInBuffer = true; } children.insert(list.remove(item)); }); return { comment: protectedComment, stylesheet: { type: 'StyleSheet', loc: null, children } }; } function compressChunk(ast, firstAtrulesAllowed, num, options) { options.logger(`Compress block #${num}`, null, true); let seed = 1; if (ast.type === 'StyleSheet') { ast.firstAtrulesAllowed = firstAtrulesAllowed; ast.id = seed++; } walk(ast, { visit: 'Atrule', enter(node) { if (node.block !== null) { node.block.id = seed++; } } }); options.logger('init', ast); // remove redundant clean(ast, options); options.logger('clean', ast); // replace nodes for shortened forms replace(ast, options); options.logger('replace', ast); // structure optimisations if (options.restructuring) { restructure(ast, options); } return ast; } function getCommentsOption(options) { let comments = 'comments' in options ? options.comments : 'exclamation'; if (typeof comments === 'boolean') { comments = comments ? 'exclamation' : false; } else if (comments !== 'exclamation' && comments !== 'first-exclamation') { comments = false; } return comments; } function getRestructureOption(options) { if ('restructure' in options) { return options.restructure; } return 'restructuring' in options ? options.restructuring : true; } function wrapBlock(block) { return new List().appendData({ type: 'Rule', loc: null, prelude: { type: 'SelectorList', loc: null, children: new List().appendData({ type: 'Selector', loc: null, children: new List().appendData({ type: 'TypeSelector', loc: null, name: 'x' }) }) }, block }); } export default function compress(ast, options) { ast = ast || { type: 'StyleSheet', loc: null, children: new List() }; options = options || {}; const compressOptions = { logger: typeof options.logger === 'function' ? options.logger : function() {}, restructuring: getRestructureOption(options), forceMediaMerge: Boolean(options.forceMediaMerge), usage: options.usage ? buildIndex(options.usage) : false }; const output = new List(); let specialComments = getCommentsOption(options); let firstAtrulesAllowed = true; let input; let chunk; let chunkNum = 1; let chunkChildren; if (options.clone) { ast = clone(ast); } if (ast.type === 'StyleSheet') { input = ast.children; ast.children = output; } else { input = wrapBlock(ast); } do { chunk = readChunk(input, Boolean(specialComments)); compressChunk(chunk.stylesheet, firstAtrulesAllowed, chunkNum++, compressOptions); chunkChildren = chunk.stylesheet.children; if (chunk.comment) { // add \n before comment if there is another content in output if (!output.isEmpty) { output.insert(List.createItem({ type: 'Raw', value: '\n' })); } output.insert(List.createItem(chunk.comment)); // add \n after comment if chunk is not empty if (!chunkChildren.isEmpty) { output.insert(List.createItem({ type: 'Raw', value: '\n' })); } } if (firstAtrulesAllowed && !chunkChildren.isEmpty) { const lastRule = chunkChildren.last; if (lastRule.type !== 'Atrule' || (lastRule.name !== 'import' && lastRule.name !== 'charset')) { firstAtrulesAllowed = false; } } if (specialComments !== 'exclamation') { specialComments = false; } output.appendList(chunkChildren); } while (!input.isEmpty); return { ast }; };