next
Version:
The React Framework
172 lines (171 loc) • 8.53 kB
JavaScript
import fs from 'fs/promises';
import path from 'path';
// NOTE: this should be updated if this loader file is moved.
const PACKAGE_ROOT = path.normalize(path.join(__dirname, '../../..'));
const TEMPLATE_FOLDER = path.join(__dirname, 'templates');
const TEMPLATES_ESM_FOLDER = path.normalize(path.join(__dirname, '../../dist/esm/build/templates'));
/**
* Load the entrypoint file from the ESM directory and performs string
* replacements of the template variables specified in the `replacements`
* argument.
*
* For non-string replacements, the template should use the
* `declare const ${key}: ${type}` syntax. to ensure that the type is correct
* and the typescript can compile. You may have to use `@ts-expect-error` to
* handle replacement values that are related to imports.
*
* @param entrypoint the entrypoint to load
* @param replacements string replacements to perform
* @param injections code injections to perform
* @param imports optional imports to insert or set to null
* @returns the loaded file with the replacements
*/ export async function loadEntrypoint(entrypoint, replacements, injections, imports) {
const filepath = path.resolve(path.join(TEMPLATES_ESM_FOLDER, `${entrypoint}.js`));
let file = await fs.readFile(filepath, 'utf8');
// Update the relative imports to be absolute. This will update any relative
// imports to be relative to the root of the `next` package.
let count = 0;
file = file.replaceAll(/from '(\..*)'|import '(\..*)'/g, function(_, fromRequest, importRequest) {
count++;
const relative = path.relative(PACKAGE_ROOT, path.resolve(TEMPLATE_FOLDER, fromRequest ?? importRequest))// Ensure that we use linux style path separators for node.
.replace(/\\/g, '/');
// Verify that the relative import is relative to the `next` package. This
// will catch cases where the constants at the top of the file were not
// updated after the file was moved.
if (!relative.startsWith('next/')) {
throw Object.defineProperty(new Error(`Invariant: Expected relative import to start with "next/", found "${relative}"`), "__NEXT_ERROR_CODE", {
value: "E214",
enumerable: false,
configurable: true
});
}
return fromRequest ? `from ${JSON.stringify(relative)}` : `import ${JSON.stringify(relative)}`;
});
// Verify that at least one import was replaced. It's the case today where
// every template file has at least one import to update, so this ensures that
// we don't accidentally remove the import replacement code or use the wrong
// template file.
if (count === 0) {
throw Object.defineProperty(new Error('Invariant: Expected to replace at least one import'), "__NEXT_ERROR_CODE", {
value: "E363",
enumerable: false,
configurable: true
});
}
const replaced = new Set();
// Replace all the template variables with the actual values. If a template
// variable is missing, throw an error.
file = file.replaceAll(new RegExp(`${Object.keys(replacements).map((k)=>`'${k}'`).join('|')}`, 'g'), (match)=>{
const key = JSON.parse(match.replace(/'/g, `"`));
if (!(key in replacements)) {
throw Object.defineProperty(new Error(`Invariant: Unexpected template variable ${key}`), "__NEXT_ERROR_CODE", {
value: "E9",
enumerable: false,
configurable: true
});
}
replaced.add(key);
return JSON.stringify(replacements[key]);
});
// Check to see if there's any remaining template variables.
let matches = file.match(/VAR_[A-Z_]+/g);
if (matches) {
throw Object.defineProperty(new Error(`Invariant: Expected to replace all template variables, found ${matches.join(', ')}`), "__NEXT_ERROR_CODE", {
value: "E415",
enumerable: false,
configurable: true
});
}
// Check to see if any template variable was provided but not used.
if (replaced.size !== Object.keys(replacements).length) {
// Find the difference between the provided replacements and the replaced
// template variables. This will let us notify the user of any template
// variables that were not used but were provided.
const difference = Object.keys(replacements).filter((key)=>!replaced.has(key));
throw Object.defineProperty(new Error(`Invariant: Expected to replace all template variables, missing ${difference.join(', ')} in template`), "__NEXT_ERROR_CODE", {
value: "E196",
enumerable: false,
configurable: true
});
}
// Replace the injections.
const injected = new Set();
if (injections) {
// Track all the injections to ensure that we're not missing any.
file = file.replaceAll(new RegExp(`// INJECT:(${Object.keys(injections).join('|')})`, 'g'), (_, key)=>{
if (!(key in injections)) {
throw Object.defineProperty(new Error(`Invariant: Unexpected injection ${key}`), "__NEXT_ERROR_CODE", {
value: "E26",
enumerable: false,
configurable: true
});
}
injected.add(key);
return `const ${key} = ${injections[key]}`;
});
}
// Check to see if there's any remaining injections.
matches = file.match(/\/\/ INJECT:[A-Za-z0-9_]+/g);
if (matches) {
throw Object.defineProperty(new Error(`Invariant: Expected to inject all injections, found ${matches.join(', ')}`), "__NEXT_ERROR_CODE", {
value: "E84",
enumerable: false,
configurable: true
});
}
// Check to see if any injection was provided but not used.
if (injected.size !== Object.keys(injections ?? {}).length) {
// Find the difference between the provided injections and the injected
// injections. This will let us notify the user of any injections that were
// not used but were provided.
const difference = Object.keys(injections ?? {}).filter((key)=>!injected.has(key));
throw Object.defineProperty(new Error(`Invariant: Expected to inject all injections, missing ${difference.join(', ')} in template`), "__NEXT_ERROR_CODE", {
value: "E382",
enumerable: false,
configurable: true
});
}
// Replace the optional imports.
const importsAdded = new Set();
if (imports) {
// Track all the imports to ensure that we're not missing any.
file = file.replaceAll(new RegExp(`// OPTIONAL_IMPORT:(\\* as )?(${Object.keys(imports).join('|')})`, 'g'), (_, asNamespace = '', key)=>{
if (!(key in imports)) {
throw Object.defineProperty(new Error(`Invariant: Unexpected optional import ${key}`), "__NEXT_ERROR_CODE", {
value: "E85",
enumerable: false,
configurable: true
});
}
importsAdded.add(key);
if (imports[key]) {
return `import ${asNamespace}${key} from ${JSON.stringify(imports[key])}`;
} else {
return `const ${key} = null`;
}
});
}
// Check to see if there's any remaining imports.
matches = file.match(/\/\/ OPTIONAL_IMPORT:(\* as )?[A-Za-z0-9_]+/g);
if (matches) {
throw Object.defineProperty(new Error(`Invariant: Expected to inject all imports, found ${matches.join(', ')}`), "__NEXT_ERROR_CODE", {
value: "E384",
enumerable: false,
configurable: true
});
}
// Check to see if any import was provided but not used.
if (importsAdded.size !== Object.keys(imports ?? {}).length) {
// Find the difference between the provided imports and the injected
// imports. This will let us notify the user of any imports that were
// not used but were provided.
const difference = Object.keys(imports ?? {}).filter((key)=>!importsAdded.has(key));
throw Object.defineProperty(new Error(`Invariant: Expected to inject all imports, missing ${difference.join(', ')} in template`), "__NEXT_ERROR_CODE", {
value: "E150",
enumerable: false,
configurable: true
});
}
return file;
}
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