feat: port loaderContext's getOptions from webpack

declarations/getLoaderOptions.d.ts

@@ -0,0 +1,4 @@
+export function getLoaderOptions(
+  options: string | object | null | undefined,
+  schema: import('./validate').Schema | null | undefined
+): object;

declarations/index.d.ts

@@ -1,3 +1,4 @@
+import { getLoaderOptions } from './getLoaderOptions';
 import { validate } from './validate';
 import { ValidationError } from './validate';
-export { validate, ValidationError };
+export { getLoaderOptions, validate, ValidationError };

package.json

@@ -43,9 +43,11 @@
     "declarations"
   ],
   "dependencies": {
+    "@types/json-parse-better-errors": "^1.0.0",
+    "@types/json-schema": "^7.0.7",
     "ajv": "^6.12.5",
     "ajv-keywords": "^3.5.2",
-    "@types/json-schema": "^7.0.7"
+    "json-parse-better-errors": "^1.0.2"
   },
   "devDependencies": {
     "@babel/cli": "^7.12.13",

src/getLoaderOptions.js

@@ -0,0 +1,53 @@
+/* eslint-disable no-param-reassign */
+
+const querystring = require('querystring');
+
+const parseJson = require('json-parse-better-errors');
+
+const { validate } = require('./validate');
+
+/**
+ * Parses the loader option if necessary, and validates it.
+ *
+ * @param {string | object | null | undefined} options a raw object, a JSON string, or a query string representing a loader option
+ * @param {import("./validate").Schema | null | undefined} schema a schema to validate the option against
+ * @return {object} the parsed loader option
+ */
+module.exports.getLoaderOptions = function getLoaderOptions(options, schema) {
+  if (typeof options === 'string') {
+    if (options.substr(0, 1) === '{' && options.substr(-1) === '}') {
+      try {
+        options = parseJson(options);
+      } catch (e) {
+        throw new Error(`Cannot parse string options: ${e.message}`);
+      }
+    } else {
+      options = querystring.parse(options, '&', '=', {
+        maxKeys: 0,
+      });
+    }
+  }
+
+  // eslint-disable-next-line no-undefined
+  if (options === null || options === undefined) {
+    options = {};
+  }
+
+  if (schema) {
+    let name = 'Loader';
+    let baseDataPath = 'options';
+    let match;
+    // eslint-disable-next-line no-cond-assign
+    if (schema.title && (match = /^(.+) (.+)$/.exec(schema.title))) {
+      [, name, baseDataPath] = match;
+    }
+    // @ts-expect-error
+    validate(schema, options, {
+      name,
+      baseDataPath,
+    });
+  }
+
+  // @ts-expect-error
+  return options;
+};

src/index.js

@@ -1,3 +1,4 @@
 const { validate, ValidationError } = require('./validate');
+const { getLoaderOptions } = require('./getLoaderOptions');
 
-module.exports = { validate, ValidationError };
+module.exports = { getLoaderOptions, validate, ValidationError };

test/__snapshots__/getLoaderOptions.test.js.snap

@@ -0,0 +1,21 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`getLoaderOptions parses and validates given JSON string 1`] = `
+"Invalid options object. CSS Loader has been initialized using an options object that does not match the API schema.
+ - options has an unknown property 'namee'. These properties are valid:
+   object { name? }"
+`;
+
+exports[`getLoaderOptions parses and validates given query string 1`] = `
+"Invalid options object. CSS Loader has been initialized using an options object that does not match the API schema.
+ - options has an unknown property 'namee'. These properties are valid:
+   object { name? }"
+`;
+
+exports[`getLoaderOptions returns and validates given object as-is 1`] = `
+"Invalid options object. CSS Loader has been initialized using an options object that does not match the API schema.
+ - options has an unknown property 'namee'. These properties are valid:
+   object { name? }"
+`;
+
+exports[`getLoaderOptions throws an error for invalid JSON 1`] = `"Cannot parse string options: Unexpected token u in JSON at position 10 while parsing near '{\\"name\\":faulse}'"`;

test/getLoaderOptions.test.js

@@ -0,0 +1,59 @@
+import { getLoaderOptions } from '../src';
+
+import schemaTitle from './fixtures/schema-title.json';
+
+describe('getLoaderOptions', () => {
+  it('returns given object as-is', () => {
+    const options = getLoaderOptions({ name: false });
+    expect(options).toEqual({ name: false });
+  });
+
+  it('returns and validates given object as-is', () => {
+    const options = getLoaderOptions({ name: false }, schemaTitle);
+    expect(options).toEqual({ name: false }, schemaTitle);
+    expect(() =>
+      getLoaderOptions({ namee: false }, schemaTitle)
+    ).toThrowErrorMatchingSnapshot();
+  });
+
+  it('parses given JSON string', () => {
+    const options = getLoaderOptions('{"name":false}');
+    expect(options).toEqual({ name: false });
+  });
+
+  it('parses and validates given JSON string', () => {
+    const options = getLoaderOptions('{"name":false}', schemaTitle);
+    expect(options).toEqual({ name: false }, schemaTitle);
+    expect(() =>
+      getLoaderOptions('{"namee":false}', schemaTitle)
+    ).toThrowErrorMatchingSnapshot();
+  });
+
+  it('throws an error for invalid JSON', () => {
+    expect(() =>
+      getLoaderOptions('{"name":faulse}')
+    ).toThrowErrorMatchingSnapshot();
+  });
+
+  it('parses given query string', () => {
+    const options = getLoaderOptions('name=false');
+    expect(options).toEqual({ name: 'false' });
+  });
+
+  it('parses and validates given query string', () => {
+    expect(() =>
+      getLoaderOptions('namee=false', schemaTitle)
+    ).toThrowErrorMatchingSnapshot();
+  });
+
+  it('returns an empty object for null', () => {
+    const options = getLoaderOptions(null);
+    expect(options).toEqual({});
+  });
+
+  it('returns an empty object for undefined', () => {
+    // eslint-disable-next-line no-undefined
+    const options = getLoaderOptions(undefined);
+    expect(options).toEqual({});
+  });
+});