node/lib/internal/modules/esm/assert.js

117 lines
3.8 KiB
JavaScript

'use strict';
const {
ArrayPrototypeFilter,
ArrayPrototypeIncludes,
ObjectKeys,
ObjectPrototypeHasOwnProperty,
ObjectValues,
} = primordials;
const { validateString } = require('internal/validators');
const {
ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE,
ERR_IMPORT_ATTRIBUTE_MISSING,
ERR_IMPORT_ATTRIBUTE_UNSUPPORTED,
} = require('internal/errors').codes;
// The HTML spec has an implied default type of `'javascript'`.
const kImplicitTypeAttribute = 'javascript';
/**
* Define a map of module formats to import attributes types (the value of
* `type` in `with { type: 'json' }`).
* @type {Map<string, string>}
*/
const formatTypeMap = {
'__proto__': null,
'builtin': kImplicitTypeAttribute,
'commonjs': kImplicitTypeAttribute,
'json': 'json',
'module': kImplicitTypeAttribute,
'wasm': kImplicitTypeAttribute, // It's unclear whether the HTML spec will require an type attribute or not for Wasm; see https://github.com/WebAssembly/esm-integration/issues/42
};
/**
* The HTML spec disallows the default type to be explicitly specified
* (for now); so `import './file.js'` is okay but
* `import './file.js' with { type: 'javascript' }` throws.
* @type {Array<string, string>}
*/
const supportedTypeAttributes = ArrayPrototypeFilter(
ObjectValues(formatTypeMap),
(type) => type !== kImplicitTypeAttribute);
/**
* Test a module's import attributes.
* @param {string} url The URL of the imported module, for error reporting.
* @param {string} format One of Node's supported translators
* @param {Record<string, string>} importAttributes Validations for the
* module import.
* @returns {true}
* @throws {TypeError} If the format and type attribute are incompatible.
*/
function validateAttributes(url, format,
importAttributes = { __proto__: null }) {
const keys = ObjectKeys(importAttributes);
for (let i = 0; i < keys.length; i++) {
if (keys[i] !== 'type') {
throw new ERR_IMPORT_ATTRIBUTE_UNSUPPORTED(keys[i], importAttributes[keys[i]]);
}
}
const validType = formatTypeMap[format];
switch (validType) {
case undefined:
// Ignore attributes for module formats we don't recognize, to allow new
// formats in the future.
return true;
case kImplicitTypeAttribute:
// This format doesn't allow an import type attribute, so the property
// must not be set on the import attributes object.
if (!ObjectPrototypeHasOwnProperty(importAttributes, 'type')) {
return true;
}
return handleInvalidType(url, importAttributes.type);
case importAttributes.type:
// The type attribute is the valid type for this format.
return true;
default:
// There is an expected type for this format, but the value of
// `importAttributes.type` might not have been it.
if (!ObjectPrototypeHasOwnProperty(importAttributes, 'type')) {
// `type` wasn't specified at all.
throw new ERR_IMPORT_ATTRIBUTE_MISSING(url, 'type', validType);
}
return handleInvalidType(url, importAttributes.type);
}
}
/**
* Throw the correct error depending on what's wrong with the type attribute.
* @param {string} url The resolved URL for the module to be imported
* @param {string} type The value of the import attributes' `type` property
*/
function handleInvalidType(url, type) {
// `type` might have not been a string.
validateString(type, 'type');
// `type` might not have been one of the types we understand.
if (!ArrayPrototypeIncludes(supportedTypeAttributes, type)) {
throw new ERR_IMPORT_ATTRIBUTE_UNSUPPORTED('type', type);
}
// `type` was the wrong value for this format.
throw new ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE(url, type);
}
module.exports = {
kImplicitTypeAttribute,
validateAttributes,
};