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101 lines
3.2 KiB
101 lines
3.2 KiB
/* |
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* MIT License http://opensource.org/licenses/MIT |
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* Author: Ben Holloway @bholloway |
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*/ |
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'use strict'; |
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var path = require('path'), |
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convert = require('convert-source-map'), |
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rework = require('rework'), |
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visit = require('rework-visit'); |
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var fileProtocol = require('../file-protocol'); |
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/** |
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* Process the given CSS content into reworked CSS content. |
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* |
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* @param {string} sourceFile The absolute path of the file being processed |
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* @param {string} sourceContent CSS content without source-map |
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* @param {{outputSourceMap: boolean, transformDeclaration:function, absSourceMap:object, |
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* sourceMapConsumer:object}} params Named parameters |
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* @return {{content: string, map: object}} Reworked CSS and optional source-map |
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*/ |
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function process(sourceFile, sourceContent, params) { |
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// embed source-map in css |
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// prepend file protocol to all sources to avoid problems with source map |
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var contentWithMap = sourceContent + ( |
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params.absSourceMap ? |
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convert.fromObject(fileProtocol.prepend(params.absSourceMap)).toComment({multiline: true}) : |
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'' |
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); |
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// need to prepend file protocol to source as well to avoid problems with source map |
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var reworked = rework(contentWithMap, {source: fileProtocol.prepend(sourceFile)}) |
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.use(reworkPlugin) |
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.toString({ |
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sourcemap : params.outputSourceMap, |
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sourcemapAsObject: params.outputSourceMap |
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}); |
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// complete with source-map |
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if (params.outputSourceMap) { |
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return { |
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content: reworked.code, |
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map : fileProtocol.remove(reworked.map) |
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}; |
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} |
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// complete without source-map |
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else { |
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return { |
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content: reworked, |
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map : null |
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}; |
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} |
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/** |
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* Plugin for css rework that follows SASS transpilation. |
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* |
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* @param {object} stylesheet AST for the CSS output from SASS |
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*/ |
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function reworkPlugin(stylesheet) { |
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// visit each node (selector) in the stylesheet recursively using the official utility method |
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// each node may have multiple declarations |
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visit(stylesheet, function visitor(declarations) { |
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if (declarations) { |
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declarations.forEach(eachDeclaration); |
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} |
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}); |
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/** |
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* Process a declaration from the syntax tree. |
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* @param declaration |
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*/ |
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function eachDeclaration(declaration) { |
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var isValid = declaration.value && (declaration.value.indexOf('url') >= 0); |
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if (isValid) { |
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// reverse the original source-map to find the original source file before transpilation |
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var startPosApparent = declaration.position.start, |
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startPosOriginal = params.sourceMapConsumer && |
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params.sourceMapConsumer.originalPositionFor(startPosApparent); |
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// we require a valid directory for the specified file |
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var directory = |
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startPosOriginal && |
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startPosOriginal.source && |
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fileProtocol.remove(path.dirname(startPosOriginal.source)); |
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if (directory) { |
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declaration.value = params.transformDeclaration(declaration.value, directory); |
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} |
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// source-map present but invalid entry |
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else if (params.sourceMapConsumer) { |
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throw new Error('source-map information is not available at url() declaration'); |
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} |
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} |
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} |
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} |
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} |
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module.exports = process;
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