parser.js

var parse5 = require( 'parse5' );
var deindent = require( './deindent' );
var hash = require( 'hash-sum' );
var cache = require( 'lru-cache' )( 100 );
var SourceMapGenerator = require( 'source-map' ).SourceMapGenerator;

var splitRE = /\r?\n/g
var emptyRE = /^\s*$/

function getCommentSymbol() {
	return '//';
}

function getAttribute( node, name ) {
	if (node.attrs) {
		var i = node.attrs.length
		var attr
		while (i--) {
			attr = node.attrs[i]
			if (attr.name === name) {
				return attr.value
			}
		}
	}
}

function commentScript( content ) {
	var symbol = getCommentSymbol();
	var lines = content.split( splitRE )
	return lines.map( function( line, index ) {
		// preserve EOL
		if (index === lines.length - 1 && emptyRE.test( line )) {
			return ''
		} else {
			return symbol + (emptyRE.test( line ) ? '' : ' ' + line)
		}
	} )
	.join( '\n' )
}

function parse( content, filename, needMap ) {
	var cacheKey = hash( filename + content )
	// source-map cache busting for hot-reloadded modules
	var filenameWithHash = filename + '?' + cacheKey
	var output = cache.get( cacheKey )
	if (output) return output

	var output = {
		template: [],
		style: [],
		script: [],
	}

	var fragment = parse5.parseFragment( content, {
		locationInfo: true
	} );

	fragment.childNodes.forEach( function( node ) {
		var tagName = node.tagName;
		var lang = getAttribute( node, 'lang' );
		var scoped = getAttribute( node, 'scoped' ) != null
		var map = null

		if (!output[tagName]) {
			return;
		}

		if (tagName === 'template') {
			node = node.content;
		}

		var start = node.childNodes[0].__location.startOffset;
		var end = node.childNodes[node.childNodes.length - 1].__location.endOffset;

		var result;
		if (tagName === 'script') {
			result = commentScript( content.slice( 0, start ) ) +
			deindent( content.slice( start, end ) ) +
			commentScript( content.slice( end ) );
		} else {
			var lineOffset = content.slice( 0, start ).split( splitRE ).length - 1
			result = deindent( content.slice( start, end ) )
			result = Array( lineOffset + 1 ).join( '\n' ) + result
		}

		if (needMap) {
			// generate source map
			map = new SourceMapGenerator()
			map.setSourceContent( filenameWithHash, content )

			// do not add mappings for comment lines - babel's source map
			// somehow gets messed up because of it
			var isCommentLine = function( line ) {
				return tagName === 'script' &&
					line.indexOf( getCommentSymbol() ) === 0
			}

			result.split( splitRE ).forEach( function( line, index ) {
				if (!emptyRE.test( line ) && !isCommentLine( line )) {
					map.addMapping( {
						source: filenameWithHash,
						original: {
							line: index + 1,
							column: 0
						},
						generated: {
							line: index + 1,
							column: 0
						}
					} )
				}
			} )
			// workaround for Webpack eval-source-map bug
			// https://github.com/webpack/webpack/pull/1816
			// in case the script was piped through another loader
			// that doesn't pass down the source map properly.
			if (tagName === 'script' && !lang) {
				result += '\n/* generated by pure-loader */\n'
			}
		}

		output[tagName].push( {
			content: result,
			lang: lang,
			scoped: scoped,
			map: map && map.toJSON()
		} );
	} );

	cache.set( cacheKey, output )

	return output
}

module.exports = parse;