next
Version:
The React Framework
175 lines (174 loc) • 7.52 kB
JavaScript
/**
* This webpack resolver is largely based on TypeScript's "paths" handling
* The TypeScript license can be found here:
* https://github.com/microsoft/TypeScript/blob/214df64e287804577afa1fea0184c18c40f7d1ca/LICENSE.txt
*/ import path from 'path';
import { debug } from 'next/dist/compiled/debug';
const log = debug('next:jsconfig-paths-plugin');
const asterisk = 0x2a;
export function hasZeroOrOneAsteriskCharacter(str) {
let seenAsterisk = false;
for(let i = 0; i < str.length; i++){
if (str.charCodeAt(i) === asterisk) {
if (!seenAsterisk) {
seenAsterisk = true;
} else {
// have already seen asterisk
return false;
}
}
}
return true;
}
/**
* Determines whether a path starts with a relative path component (i.e. `.` or `..`).
*/ export function pathIsRelative(testPath) {
return /^\.\.?($|[\\/])/.test(testPath);
}
export function tryParsePattern(pattern) {
// This should be verified outside of here and a proper error thrown.
const indexOfStar = pattern.indexOf('*');
return indexOfStar === -1 ? undefined : {
prefix: pattern.slice(0, indexOfStar),
suffix: pattern.slice(indexOfStar + 1)
};
}
function isPatternMatch({ prefix, suffix }, candidate) {
return candidate.length >= prefix.length + suffix.length && candidate.startsWith(prefix) && candidate.endsWith(suffix);
}
/** Return the object corresponding to the best pattern to match `candidate`. */ export function findBestPatternMatch(values, getPattern, candidate) {
let matchedValue;
// use length of prefix as betterness criteria
let longestMatchPrefixLength = -1;
for (const v of values){
const pattern = getPattern(v);
if (isPatternMatch(pattern, candidate) && pattern.prefix.length > longestMatchPrefixLength) {
longestMatchPrefixLength = pattern.prefix.length;
matchedValue = v;
}
}
return matchedValue;
}
/**
* patternStrings contains both pattern strings (containing "*") and regular strings.
* Return an exact match if possible, or a pattern match, or undefined.
* (These are verified by verifyCompilerOptions to have 0 or 1 "*" characters.)
*/ export function matchPatternOrExact(patternStrings, candidate) {
const patterns = [];
for (const patternString of patternStrings){
if (!hasZeroOrOneAsteriskCharacter(patternString)) continue;
const pattern = tryParsePattern(patternString);
if (pattern) {
patterns.push(pattern);
} else if (patternString === candidate) {
// pattern was matched as is - no need to search further
return patternString;
}
}
return findBestPatternMatch(patterns, (_)=>_, candidate);
}
/**
* Tests whether a value is string
*/ export function isString(text) {
return typeof text === 'string';
}
/**
* Given that candidate matches pattern, returns the text matching the '*'.
* E.g.: matchedText(tryParsePattern("foo*baz"), "foobarbaz") === "bar"
*/ export function matchedText(pattern, candidate) {
return candidate.substring(pattern.prefix.length, candidate.length - pattern.suffix.length);
}
export function patternText({ prefix, suffix }) {
return `${prefix}*${suffix}`;
}
/**
* Calls the iterator function for each entry of the array
* until the first result or error is reached
*/ function forEachBail(array, iterator, callback) {
if (array.length === 0) return callback();
let i = 0;
const next = ()=>{
let loop = undefined;
iterator(array[i++], (err, result)=>{
if (err || result !== undefined || i >= array.length) {
return callback(err, result);
}
if (loop === false) while(next());
loop = true;
});
if (!loop) loop = false;
return loop;
};
while(next());
}
const NODE_MODULES_REGEX = /node_modules/;
export class JsConfigPathsPlugin {
constructor(paths, resolvedBaseUrl){
this.paths = paths;
this.resolvedBaseUrl = resolvedBaseUrl;
this.jsConfigPlugin = true;
log('tsconfig.json or jsconfig.json paths: %O', paths);
log('resolved baseUrl: %s', resolvedBaseUrl);
}
apply(resolver) {
const target = resolver.ensureHook('resolve');
resolver.getHook('described-resolve').tapAsync('JsConfigPathsPlugin', (request, resolveContext, callback)=>{
const resolvedBaseUrl = this.resolvedBaseUrl;
if (resolvedBaseUrl === undefined) {
return callback();
}
const paths = this.paths;
const pathsKeys = Object.keys(paths);
// If no aliases are added bail out
if (pathsKeys.length === 0) {
log('paths are empty, bailing out');
return callback();
}
const moduleName = request.request;
// Exclude node_modules from paths support (speeds up resolving)
if (request.path.match(NODE_MODULES_REGEX)) {
log('skipping request as it is inside node_modules %s', moduleName);
return callback();
}
if (path.posix.isAbsolute(moduleName) || process.platform === 'win32' && path.win32.isAbsolute(moduleName)) {
log('skipping request as it is an absolute path %s', moduleName);
return callback();
}
if (pathIsRelative(moduleName)) {
log('skipping request as it is a relative path %s', moduleName);
return callback();
}
// log('starting to resolve request %s', moduleName)
// If the module name does not match any of the patterns in `paths` we hand off resolving to webpack
const matchedPattern = matchPatternOrExact(pathsKeys, moduleName);
if (!matchedPattern) {
log('moduleName did not match any paths pattern %s', moduleName);
return callback();
}
const matchedStar = isString(matchedPattern) ? undefined : matchedText(matchedPattern, moduleName);
const matchedPatternText = isString(matchedPattern) ? matchedPattern : patternText(matchedPattern);
let triedPaths = [];
forEachBail(paths[matchedPatternText], (subst, pathCallback)=>{
const curPath = matchedStar ? subst.replace('*', matchedStar) : subst;
// Ensure .d.ts is not matched
if (curPath.endsWith('.d.ts')) {
// try next path candidate
return pathCallback();
}
const candidate = path.join(resolvedBaseUrl.baseUrl, curPath);
const obj = Object.assign({}, request, {
request: candidate
});
resolver.doResolve(target, obj, `Aliased with tsconfig.json or jsconfig.json ${matchedPatternText} to ${candidate}`, resolveContext, (resolverErr, resolverResult)=>{
if (resolverErr || resolverResult === undefined) {
triedPaths.push(candidate);
// try next path candidate
return pathCallback();
}
return pathCallback(resolverErr, resolverResult);
});
}, callback);
});
}
}
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