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refactor: loader (#935)
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@evilebottnawi
evilebottnawi committed May 27, 2019
1 parent 9dabcec commit 38ff645
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Showing 2 changed files with 248 additions and 199 deletions.
230 changes: 32 additions & 198 deletions src/index.js
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Expand Up @@ -5,29 +5,26 @@
import validateOptions from 'schema-utils';
import postcss from 'postcss';
import postcssPkg from 'postcss/package.json';
import localByDefault from 'postcss-modules-local-by-default';
import extractImports from 'postcss-modules-extract-imports';
import modulesScope from 'postcss-modules-scope';
import modulesValues from 'postcss-modules-values';

import {
getOptions,
isUrlRequest,
urlToRequest,
getRemainingRequest,
getCurrentRequest,
stringifyRequest,
} from 'loader-utils';
import normalizePath from 'normalize-path';

import schema from './options.json';
import { importParser, icssParser, urlParser } from './plugins';
import {
getLocalIdent,
getImportPrefix,
normalizeSourceMap,
getModulesPlugins,
placholderRegExps,
camelCase,
dashesCamelCase,
getImportPrefix,
getImportItemReplacer,
getFilter,
getExports,
getImports,
} from './utils';
import Warning from './Warning';
import CssSyntaxError from './CssSyntaxError';
Expand All @@ -40,35 +37,14 @@ export default function loader(content, map, meta) {
const callback = this.async();
const sourceMap = options.sourceMap || false;

/* eslint-disable no-param-reassign */
if (sourceMap) {
if (map) {
// Some loader emit source map as string
// Strip any JSON XSSI avoidance prefix from the string (as documented in the source maps specification), and then parse the string as JSON.
if (typeof map === 'string') {
map = JSON.parse(map.replace(/^\)]}'[^\n]*\n/, ''));
}

// Source maps should use forward slash because it is URLs (https://github.com/mozilla/source-map/issues/91)
// We should normalize path because previous loaders like `sass-loader` using backslash when generate source map

if (map.file) {
map.file = normalizePath(map.file);
}

if (map.sourceRoot) {
map.sourceRoot = normalizePath(map.sourceRoot);
}

if (map.sources) {
map.sources = map.sources.map((source) => normalizePath(source));
}
}
if (sourceMap && map) {
// eslint-disable-next-line no-param-reassign
map = normalizeSourceMap(map);
} else {
// Some loaders (example `"postcss-loader": "1.x.x"`) always generates source map, we should remove it
// eslint-disable-next-line no-param-reassign
map = null;
}
/* eslint-enable no-param-reassign */

// Reuse CSS AST (PostCSS AST e.g 'postcss-loader') to avoid reparsing
if (meta) {
Expand All @@ -83,32 +59,7 @@ export default function loader(content, map, meta) {
const plugins = [];

if (options.modules) {
const loaderContext = this;
const mode =
typeof options.modules === 'boolean' ? 'local' : options.modules;

plugins.push(
modulesValues,
localByDefault({ mode }),
extractImports(),
modulesScope({
generateScopedName: function generateScopedName(exportName) {
const localIdentName = options.localIdentName || '[hash:base64]';
const customGetLocalIdent = options.getLocalIdent || getLocalIdent;

return customGetLocalIdent(
loaderContext,
localIdentName,
exportName,
{
regExp: options.localIdentRegExp,
hashPrefix: options.hashPrefix || '',
context: options.context,
}
);
},
})
);
plugins.push(...getModulesPlugins(options, this));
}

if (options.import !== false) {
Expand Down Expand Up @@ -153,93 +104,22 @@ export default function loader(content, map, meta) {
.forEach((warning) => this.emitWarning(new Warning(warning)));

const messages = result.messages || [];
const { exportOnlyLocals, importLoaders, camelCase } = options;

// Run other loader (`postcss-loader`, `sass-loader` and etc) for importing CSS
const importUrlPrefix = getImportPrefix(this, options.importLoaders);
const importPrefix = getImportPrefix(this, importLoaders);

// Prepare replacer to change from `___CSS_LOADER_IMPORT___INDEX___` to `require('./file.css').locals`
const importItemReplacer = (placeholder) => {
const match = placholderRegExps.importItem.exec(placeholder);
const idx = Number(match[1]);

const message = messages.find(
// eslint-disable-next-line no-shadow
(message) =>
message.type === 'icss-import' &&
message.item &&
message.item.index === idx
);

if (!message) {
return placeholder;
}

const { item } = message;
const importUrl = importUrlPrefix + urlToRequest(item.url);

if (options.exportOnlyLocals) {
return `" + require(${stringifyRequest(
this,
importUrl
)})[${JSON.stringify(item.export)}] + "`;
}

return `" + require(${stringifyRequest(
this,
importUrl
)}).locals[${JSON.stringify(item.export)}] + "`;
};

const exports = messages
.filter((message) => message.type === 'export')
.reduce((accumulator, message) => {
const { key, value } = message.item;

let valueAsString = JSON.stringify(value);

valueAsString = valueAsString.replace(
placholderRegExps.importItemG,
importItemReplacer
);

function addEntry(k) {
accumulator.push(`\t${JSON.stringify(k)}: ${valueAsString}`);
}

let targetKey;

switch (options.camelCase) {
case true:
addEntry(key);
targetKey = camelCase(key);

if (targetKey !== key) {
addEntry(targetKey);
}
break;
case 'dashes':
addEntry(key);
targetKey = dashesCamelCase(key);

if (targetKey !== key) {
addEntry(targetKey);
}
break;
case 'only':
addEntry(camelCase(key));
break;
case 'dashesOnly':
addEntry(dashesCamelCase(key));
break;
default:
addEntry(key);
break;
}
const importItemReplacer = getImportItemReplacer(
messages,
this,
importPrefix,
exportOnlyLocals
);

return accumulator;
}, []);
const exports = getExports(messages, camelCase, importItemReplacer);

if (options.exportOnlyLocals) {
if (exportOnlyLocals) {
return callback(
null,
exports.length > 0
Expand All @@ -248,69 +128,23 @@ export default function loader(content, map, meta) {
);
}

const imports = messages
.filter((message) => message.type === 'import')
.map((message) => {
const { url } = message.item;
const media = message.item.media || '';

if (!isUrlRequest(url)) {
return `exports.push([module.id, ${JSON.stringify(
`@import url(${url});`
)}, ${JSON.stringify(media)}]);`;
}

const importUrl = importUrlPrefix + urlToRequest(url);

return `exports.i(require(${stringifyRequest(
this,
importUrl
)}), ${JSON.stringify(media)});`;
}, this);

let cssAsString = JSON.stringify(result.css).replace(
placholderRegExps.importItemG,
importItemReplacer
);

// Helper for ensuring valid CSS strings from requires
let hasUrlEscapeHelper = false;

messages
.filter((message) => message.type === 'url')
.forEach((message) => {
if (!hasUrlEscapeHelper) {
imports.push(
`var urlEscape = require(${stringifyRequest(
this,
require.resolve('./runtime/url-escape.js')
)});`
);

hasUrlEscapeHelper = true;
}

const { item } = message;
const { url, placeholder, needQuotes } = item;
// Remove `#hash` and `?#hash` from `require`
const [normalizedUrl, singleQuery, hashValue] = url.split(/(\?)?#/);
const hash =
singleQuery || hashValue
? `"${singleQuery ? '?' : ''}${hashValue ? `#${hashValue}` : ''}"`
: '';
const imports = getImports(messages, importPrefix, this, (message) => {
if (message.type !== 'url') {
return;
}

imports.push(
`var ${placeholder} = urlEscape(require(${stringifyRequest(
this,
urlToRequest(normalizedUrl)
)})${hash ? ` + ${hash}` : ''}${needQuotes ? ', true' : ''});`
);
const { placeholder } = message.item;

cssAsString = cssAsString.replace(
new RegExp(placeholder, 'g'),
() => `" + ${placeholder} + "`
);
});
cssAsString = cssAsString.replace(
new RegExp(placeholder, 'g'),
() => `" + ${placeholder} + "`
);
});

const runtimeCode = `exports = module.exports = require(${stringifyRequest(
this,
Expand Down

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