240 lines
6.7 KiB
JavaScript

import { init, parse } from 'es-module-lexer';
import assert from 'node:assert';
import { removeSlashes } from 'slashes';
import module, { createRequire } from 'node:module';
import { dirname } from 'node:path';
const separatorRegex = /^(?:\s+|,)$/u;
const skipSeparators = (imported, i) => {
while (i < imported.length && separatorRegex.test(imported[i])) {
i++;
}
return i;
};
const skipNonSeparators = (imported, i) => {
while (i < imported.length && !separatorRegex.test(imported[i])) {
i++;
}
return i;
};
const parseDefaultImport = (importClauseString, i) => {
const startIndex = i;
i = skipNonSeparators(importClauseString, i);
return {
defaultImport: importClauseString.slice(startIndex, i),
i
};
};
const parseNamedImports = (importClauseString, i) => {
const startIndex = ++i;
while (i < importClauseString.length && importClauseString[i] !== `}`) {
i++;
}
const namedImports = importClauseString.slice(startIndex, i++).split(`,`).map(namedImport => {
namedImport = namedImport.trim();
if (namedImport.includes(` `)) {
const components = namedImport.split(` `);
return {
specifier: components[0],
binding: components.at(-1)
};
}
return {
specifier: namedImport,
binding: namedImport
};
}).filter(({
specifier
}) => specifier.length > 0);
return {
namedImports,
i
};
};
const parseNamespaceImport = (importClauseString, i) => {
i++;
i = skipSeparators(importClauseString, i);
i += `as`.length;
i = skipSeparators(importClauseString, i);
const startIndex = i;
i = skipNonSeparators(importClauseString, i);
return {
namespaceImport: importClauseString.slice(startIndex, i),
i
};
};
// Assumes import clause is syntactically valid
const parseImportClause = importClauseString => {
let defaultImport;
let namespaceImport;
const namedImports = [];
for (let i = 0; i < importClauseString.length; i++) {
if (separatorRegex.test(importClauseString[i])) {
continue;
}
if (importClauseString[i] === `{`) {
let newNamedImports;
({
namedImports: newNamedImports,
i
} = parseNamedImports(importClauseString, i));
namedImports.push(...newNamedImports);
} else if (importClauseString[i] === `*`) {
({
namespaceImport,
i
} = parseNamespaceImport(importClauseString, i));
} else {
({
defaultImport,
i
} = parseDefaultImport(importClauseString, i));
}
}
return {
default: defaultImport,
namespace: namespaceImport,
named: namedImports
};
};
// Assumes the string is syntactically valid
const isConstantStringLiteral = stringLiteral => {
const quote = [`'`, `"`, `\``].find(quoteCandidate => stringLiteral.startsWith(quoteCandidate) && stringLiteral.endsWith(quoteCandidate));
if (quote == null) {
return false;
}
for (let i = 1; i < stringLiteral.length - 1; i++) {
// Check for end of string literal before end of stringLiteral
if (stringLiteral[i] === quote && stringLiteral[i - 1] !== `\\`) {
return false;
}
// Check for interpolated value in template literal
if (quote === `\`` && stringLiteral.slice(i, i + 2) === `\${` && stringLiteral[i - 1] !== `\\`) {
return false;
}
}
return true;
};
const builtinModules = new Set(module.builtinModules);
const parseType = moduleSpecifier => {
if (moduleSpecifier.length === 0) {
return `invalid`;
}
if (moduleSpecifier.startsWith(`/`)) {
return `absolute`;
}
if (moduleSpecifier.startsWith(`.`)) {
return `relative`;
}
if (builtinModules.has(moduleSpecifier)) {
return `builtin`;
}
return `package`;
};
const require = createRequire(import.meta.url);
const resolve = (from, to) => {
try {
return require.resolve(to, {
paths: [dirname(from)]
});
} catch {
return undefined;
}
};
const parseModuleSpecifier = (moduleSpecifierString, {
isDynamicImport,
resolveFrom
}) => {
assert(isDynamicImport || isConstantStringLiteral(moduleSpecifierString));
const {
isConstant,
value
} = !isDynamicImport || isConstantStringLiteral(moduleSpecifierString) ? {
isConstant: true,
value: removeSlashes(moduleSpecifierString.slice(1, -1))
} : {
isConstant: false,
value: undefined
};
return {
type: isConstant ? parseType(value) : `unknown`,
isConstant,
code: moduleSpecifierString,
value,
resolved: typeof resolveFrom === `string` && isConstant ? resolve(resolveFrom, value) : undefined
};
};
const wasmLoadPromise = init;
const parseImports = async (code, options) => {
await wasmLoadPromise;
return parseImportsSync(code, options);
};
const parseImportsSync = (code, {
resolveFrom
} = {}) => {
const result = parse(code, resolveFrom == null ? undefined : resolveFrom);
if (!Array.isArray(result)) {
throw new TypeError(`Expected WASM to be loaded before calling parseImportsSync`);
}
const [imports] = result;
return {
*[Symbol.iterator]() {
for (let {
d: dynamicImportStartIndex,
ss: statementStartIndex,
s: moduleSpecifierStartIndex,
e: moduleSpecifierEndIndexExclusive
} of imports) {
const isImportMeta = dynamicImportStartIndex === -2;
if (isImportMeta) {
continue;
}
const isDynamicImport = dynamicImportStartIndex > -1;
// Include string literal quotes in character range
if (!isDynamicImport) {
moduleSpecifierStartIndex--;
moduleSpecifierEndIndexExclusive++;
}
const moduleSpecifierString = code.slice(moduleSpecifierStartIndex, moduleSpecifierEndIndexExclusive);
const moduleSpecifier = {
startIndex: moduleSpecifierStartIndex,
endIndex: moduleSpecifierEndIndexExclusive,
...parseModuleSpecifier(moduleSpecifierString, {
isDynamicImport,
resolveFrom
})
};
let importClause;
if (!isDynamicImport) {
let importClauseString = code.slice(statementStartIndex + `import`.length, moduleSpecifierStartIndex).trim();
if (importClauseString.endsWith(`from`)) {
importClauseString = importClauseString.slice(0, Math.max(0, importClauseString.length - `from`.length));
}
importClause = parseImportClause(importClauseString);
}
yield {
startIndex: statementStartIndex,
// Include the closing parenthesis for dynamic import
endIndex: isDynamicImport ? moduleSpecifierEndIndexExclusive + 1 : moduleSpecifierEndIndexExclusive,
isDynamicImport,
moduleSpecifier,
importClause
};
}
}
};
};
export { parseImports, parseImportsSync, wasmLoadPromise };