package.lib.previous-map.js Maven / Gradle / Ivy
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Tool for transforming styles with JS plugins
'use strict'
let { SourceMapConsumer, SourceMapGenerator } = require('source-map-js')
let { existsSync, readFileSync } = require('fs')
let { dirname, join } = require('path')
function fromBase64(str) {
if (Buffer) {
return Buffer.from(str, 'base64').toString()
} else {
/* c8 ignore next 2 */
return window.atob(str)
}
}
class PreviousMap {
constructor(css, opts) {
if (opts.map === false) return
this.loadAnnotation(css)
this.inline = this.startWith(this.annotation, 'data:')
let prev = opts.map ? opts.map.prev : undefined
let text = this.loadMap(opts.from, prev)
if (!this.mapFile && opts.from) {
this.mapFile = opts.from
}
if (this.mapFile) this.root = dirname(this.mapFile)
if (text) this.text = text
}
consumer() {
if (!this.consumerCache) {
this.consumerCache = new SourceMapConsumer(this.text)
}
return this.consumerCache
}
decodeInline(text) {
let baseCharsetUri = /^data:application\/json;charset=utf-?8;base64,/
let baseUri = /^data:application\/json;base64,/
let charsetUri = /^data:application\/json;charset=utf-?8,/
let uri = /^data:application\/json,/
let uriMatch = text.match(charsetUri) || text.match(uri)
if (uriMatch) {
return decodeURIComponent(text.substr(uriMatch[0].length))
}
let baseUriMatch = text.match(baseCharsetUri) || text.match(baseUri)
if (baseUriMatch) {
return fromBase64(text.substr(baseUriMatch[0].length))
}
let encoding = text.match(/data:application\/json;([^,]+),/)[1]
throw new Error('Unsupported source map encoding ' + encoding)
}
getAnnotationURL(sourceMapString) {
return sourceMapString.replace(/^\/\*\s*# sourceMappingURL=/, '').trim()
}
isMap(map) {
if (typeof map !== 'object') return false
return (
typeof map.mappings === 'string' ||
typeof map._mappings === 'string' ||
Array.isArray(map.sections)
)
}
loadAnnotation(css) {
let comments = css.match(/\/\*\s*# sourceMappingURL=/g)
if (!comments) return
// sourceMappingURLs from comments, strings, etc.
let start = css.lastIndexOf(comments.pop())
let end = css.indexOf('*/', start)
if (start > -1 && end > -1) {
// Locate the last sourceMappingURL to avoid pickin
this.annotation = this.getAnnotationURL(css.substring(start, end))
}
}
loadFile(path) {
this.root = dirname(path)
if (existsSync(path)) {
this.mapFile = path
return readFileSync(path, 'utf-8').toString().trim()
}
}
loadMap(file, prev) {
if (prev === false) return false
if (prev) {
if (typeof prev === 'string') {
return prev
} else if (typeof prev === 'function') {
let prevPath = prev(file)
if (prevPath) {
let map = this.loadFile(prevPath)
if (!map) {
throw new Error(
'Unable to load previous source map: ' + prevPath.toString()
)
}
return map
}
} else if (prev instanceof SourceMapConsumer) {
return SourceMapGenerator.fromSourceMap(prev).toString()
} else if (prev instanceof SourceMapGenerator) {
return prev.toString()
} else if (this.isMap(prev)) {
return JSON.stringify(prev)
} else {
throw new Error(
'Unsupported previous source map format: ' + prev.toString()
)
}
} else if (this.inline) {
return this.decodeInline(this.annotation)
} else if (this.annotation) {
let map = this.annotation
if (file) map = join(dirname(file), map)
return this.loadFile(map)
}
}
startWith(string, start) {
if (!string) return false
return string.substr(0, start.length) === start
}
withContent() {
return !!(
this.consumer().sourcesContent &&
this.consumer().sourcesContent.length > 0
)
}
}
module.exports = PreviousMap
PreviousMap.default = PreviousMap
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