You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
73 lines
2.1 KiB
73 lines
2.1 KiB
// vue compiler module for transforming `img:srcset` to a number of `require`s
|
|
|
|
import { urlToRequire, ASTNode } from './utils'
|
|
import { TransformAssetUrlsOptions } from './assetUrl'
|
|
|
|
interface ImageCandidate {
|
|
require: string
|
|
descriptor: string
|
|
}
|
|
|
|
export default (transformAssetUrlsOptions?: TransformAssetUrlsOptions) => ({
|
|
postTransformNode: (node: ASTNode) => {
|
|
transform(node, transformAssetUrlsOptions)
|
|
}
|
|
})
|
|
|
|
// http://w3c.github.io/html/semantics-embedded-content.html#ref-for-image-candidate-string-5
|
|
const escapedSpaceCharacters = /( |\\t|\\n|\\f|\\r)+/g
|
|
|
|
function transform(
|
|
node: ASTNode,
|
|
transformAssetUrlsOptions?: TransformAssetUrlsOptions
|
|
) {
|
|
const tags = ['img', 'source']
|
|
|
|
if (tags.indexOf(node.tag) !== -1 && node.attrs) {
|
|
node.attrs.forEach(attr => {
|
|
if (attr.name === 'srcset') {
|
|
// same logic as in transform-require.js
|
|
const value = attr.value
|
|
const isStatic =
|
|
value.charAt(0) === '"' && value.charAt(value.length - 1) === '"'
|
|
if (!isStatic) {
|
|
return
|
|
}
|
|
|
|
const imageCandidates: ImageCandidate[] = value
|
|
.substr(1, value.length - 2)
|
|
.split(',')
|
|
.map(s => {
|
|
// The attribute value arrives here with all whitespace, except
|
|
// normal spaces, represented by escape sequences
|
|
const [url, descriptor] = s
|
|
.replace(escapedSpaceCharacters, ' ')
|
|
.trim()
|
|
.split(' ', 2)
|
|
return {
|
|
require: urlToRequire(url, transformAssetUrlsOptions),
|
|
descriptor
|
|
}
|
|
})
|
|
|
|
// "require(url1)"
|
|
// "require(url1) 1x"
|
|
// "require(url1), require(url2)"
|
|
// "require(url1), require(url2) 2x"
|
|
// "require(url1) 1x, require(url2)"
|
|
// "require(url1) 1x, require(url2) 2x"
|
|
const code = imageCandidates
|
|
.map(
|
|
({ require, descriptor }) =>
|
|
`${require} + "${descriptor ? ' ' + descriptor : ''}, " + `
|
|
)
|
|
.join('')
|
|
.slice(0, -6)
|
|
.concat('"')
|
|
.replace(/ \+ ""$/, '')
|
|
|
|
attr.value = code
|
|
}
|
|
})
|
|
}
|
|
}
|
|
|