CasperSecurity
import LRU from 'quick-lru'
import * as sharedState from './sharedState'
import { generateRules } from './generateRules'
import bigSign from '../util/bigSign'
import log from '../util/log'
import cloneNodes from '../util/cloneNodes'
import { defaultExtractor } from './defaultExtractor'
let env = sharedState.env
const builtInExtractors = {
DEFAULT: defaultExtractor,
}
const builtInTransformers = {
DEFAULT: (content) => content,
svelte: (content) => content.replace(/(?:^|\s)class:/g, ' '),
}
function getExtractor(tailwindConfig, fileExtension) {
let extractors = tailwindConfig.content.extract
return (
extractors[fileExtension] ||
extractors.DEFAULT ||
builtInExtractors[fileExtension] ||
builtInExtractors.DEFAULT
)
}
function getTransformer(tailwindConfig, fileExtension) {
let transformers = tailwindConfig.content.transform
return (
transformers[fileExtension] ||
transformers.DEFAULT ||
builtInTransformers[fileExtension] ||
builtInTransformers.DEFAULT
)
}
let extractorCache = new WeakMap()
// Scans template contents for possible classes. This is a hot path on initial build but
// not too important for subsequent builds. The faster the better though — if we can speed
// up these regexes by 50% that could cut initial build time by like 20%.
function getClassCandidates(content, extractor, candidates, seen) {
if (!extractorCache.has(extractor)) {
extractorCache.set(extractor, new LRU({ maxSize: 25000 }))
}
for (let line of content.split('\n')) {
line = line.trim()
if (seen.has(line)) {
continue
}
seen.add(line)
if (extractorCache.get(extractor).has(line)) {
for (let match of extractorCache.get(extractor).get(line)) {
candidates.add(match)
}
} else {
let extractorMatches = extractor(line).filter((s) => s !== '!*')
let lineMatchesSet = new Set(extractorMatches)
for (let match of lineMatchesSet) {
candidates.add(match)
}
extractorCache.get(extractor).set(line, lineMatchesSet)
}
}
}
function buildStylesheet(rules, context) {
let sortedRules = rules.sort(([a], [z]) => bigSign(a - z))
let returnValue = {
base: new Set(),
defaults: new Set(),
components: new Set(),
utilities: new Set(),
variants: new Set(),
// All the CSS that is not Tailwind related can be put in this bucket. This
// will make it easier to later use this information when we want to
// `@apply` for example. The main reason we do this here is because we
// still need to make sure the order is correct. Last but not least, we
// will make sure to always re-inject this section into the css, even if
// certain rules were not used. This means that it will look like a no-op
// from the user's perspective, but we gathered all the useful information
// we need.
user: new Set(),
}
for (let [sort, rule] of sortedRules) {
if (sort >= context.minimumScreen) {
returnValue.variants.add(rule)
continue
}
if (sort & context.layerOrder.base) {
returnValue.base.add(rule)
continue
}
if (sort & context.layerOrder.defaults) {
returnValue.defaults.add(rule)
continue
}
if (sort & context.layerOrder.components) {
returnValue.components.add(rule)
continue
}
if (sort & context.layerOrder.utilities) {
returnValue.utilities.add(rule)
continue
}
if (sort & context.layerOrder.user) {
returnValue.user.add(rule)
continue
}
}
return returnValue
}
export default function expandTailwindAtRules(context) {
return (root) => {
let layerNodes = {
base: null,
components: null,
utilities: null,
variants: null,
}
root.walkAtRules((rule) => {
// Make sure this file contains Tailwind directives. If not, we can save
// a lot of work and bail early. Also we don't have to register our touch
// file as a dependency since the output of this CSS does not depend on
// the source of any templates. Think Vue <style> blocks for example.
if (rule.name === 'tailwind') {
if (Object.keys(layerNodes).includes(rule.params)) {
layerNodes[rule.params] = rule
}
}
})
if (Object.values(layerNodes).every((n) => n === null)) {
return root
}
// ---
// Find potential rules in changed files
let candidates = new Set(['*'])
let seen = new Set()
env.DEBUG && console.time('Reading changed files')
for (let { content, extension } of context.changedContent) {
let transformer = getTransformer(context.tailwindConfig, extension)
let extractor = getExtractor(context.tailwindConfig, extension)
getClassCandidates(transformer(content), extractor, candidates, seen)
}
env.DEBUG && console.timeEnd('Reading changed files')
// ---
// Generate the actual CSS
let classCacheCount = context.classCache.size
env.DEBUG && console.time('Generate rules')
let rules = generateRules(candidates, context)
env.DEBUG && console.timeEnd('Generate rules')
// We only ever add to the classCache, so if it didn't grow, there is nothing new.
env.DEBUG && console.time('Build stylesheet')
if (context.stylesheetCache === null || context.classCache.size !== classCacheCount) {
for (let rule of rules) {
context.ruleCache.add(rule)
}
context.stylesheetCache = buildStylesheet([...context.ruleCache], context)
}
env.DEBUG && console.timeEnd('Build stylesheet')
let {
defaults: defaultNodes,
base: baseNodes,
components: componentNodes,
utilities: utilityNodes,
variants: screenNodes,
} = context.stylesheetCache
// ---
// Replace any Tailwind directives with generated CSS
if (layerNodes.base) {
layerNodes.base.before(cloneNodes([...baseNodes, ...defaultNodes], layerNodes.base.source))
layerNodes.base.remove()
}
if (layerNodes.components) {
layerNodes.components.before(cloneNodes([...componentNodes], layerNodes.components.source))
layerNodes.components.remove()
}
if (layerNodes.utilities) {
layerNodes.utilities.before(cloneNodes([...utilityNodes], layerNodes.utilities.source))
layerNodes.utilities.remove()
}
// We do post-filtering to not alter the emitted order of the variants
const variantNodes = Array.from(screenNodes).filter((node) => {
const parentLayer = node.raws.tailwind?.parentLayer
if (parentLayer === 'components') {
return layerNodes.components !== null
}
if (parentLayer === 'utilities') {
return layerNodes.utilities !== null
}
return true
})
if (layerNodes.variants) {
layerNodes.variants.before(cloneNodes(variantNodes, layerNodes.variants.source))
layerNodes.variants.remove()
} else if (variantNodes.length > 0) {
root.append(cloneNodes(variantNodes, root.source))
}
// If we've got a utility layer and no utilities are generated there's likely something wrong
const hasUtilityVariants = variantNodes.some(
(node) => node.raws.tailwind?.parentLayer === 'utilities'
)
if (layerNodes.utilities && utilityNodes.size === 0 && !hasUtilityVariants) {
log.warn('content-problems', [
'No utilities were generated there is likely a problem with the `content` key in the tailwind config. For more information see the documentation: https://tailwindcss.com/docs/content-configuration',
])
}
// ---
if (env.DEBUG) {
console.log('Potential classes: ', candidates.size)
console.log('Active contexts: ', sharedState.contextSourcesMap.size)
}
// Clear the cache for the changed files
context.changedContent = []
// Cleanup any leftover @layer atrules
root.walkAtRules('layer', (rule) => {
if (Object.keys(layerNodes).includes(rule.params)) {
rule.remove()
}
})
}
}