Simplify project a bit (#25)

* Simplify project by removing `exclude` function

* Remove `test:typescript` script

The test script runs `tsc` as part of the `pretest` script anyway

* Make sure to now overwrite properties by checking for them

* Simplify more

* Change condition

package.json

@@ -26,9 +26,7 @@
     "scripts": {
         "build": "tsc",
         "pretest": "npm run build",
-        "test": "npm run test:node && npm run test:typescript",
-        "test:node": "NODE_ENV=test node ./test/index.js",
-        "test:typescript": "tsc test/typings.ts dist/index.d.ts --noEmit"
+        "test": "NODE_ENV=test node ./test/index.js"
     },
     "devDependencies": {
         "typescript": "^4.4.3"

src/index.ts

@@ -1,56 +1,26 @@
-/**
- * Return a function that will copy properties from
- * one object to another excluding any originally
- * listed. Returned function will create a new `{}`.
- *
- * @param {String} excluded properties ...
- * @return {Function}
- */
-function exclude(...args: string[]): (a: {}, b?: {}) => Record<string, unknown> {
-  var excludes = args
-
-  function excludeProps (res: Record<string, unknown>, obj: Record<string, unknown>) {
-    Object.keys(obj).forEach(function (key) {
-      if (!~excludes.indexOf(key)) res[key] = obj[key];
-    });
-  }
-
-  return function extendExclude () {
-    var args = [].slice.call(arguments)
-      , i = 0
-      , res = {};
-
-    for (; i < args.length; i++) {
-      excludeProps(res, args[i]);
-    }
-
-    return res;
-  };
-};
-
 export default class AssertionError<T> extends Error {
   name = 'AssertionError'
   showDiff: boolean
   [key: string]: any
 
-  constructor(message: string, _props?: T, ssf?: Function) {
-    super()
-    var extend = exclude('name', 'message', 'stack', 'constructor', 'toJSON')
-      , props = extend(_props || {});
+  constructor(message: string, props?: T, ssf?: Function) {
+    super(message)
 
     // default values
     this.message = message || 'Unspecified AssertionError';
     this.showDiff = false;
 
     // copy from properties
     for (var key in props) {
-      this[key] = props[key];
+      if (!(key in this)) {
+        // @ts-ignore
+        this[key] = props[key];
+      }
     }
 
     // capture stack trace
-    ssf = ssf || AssertionError;
     if ((Error as any).captureStackTrace) {
-      (Error as any).captureStackTrace(this, ssf);
+      (Error as any).captureStackTrace(this, ssf || AssertionError);
     } else {
       try {
         throw new Error();
@@ -60,21 +30,15 @@ export default class AssertionError<T> extends Error {
     }
   }
 
-  /**
-   * Allow errors to be converted to JSON for static transfer.
-   *
-   * @param {Boolean} include stack (default: `true`)
-   * @return {Object} object that can be `JSON.stringify`
-   */
-
-  toJSON(stack: boolean) {
-    var extend = exclude('constructor', 'toJSON', 'stack')
-      , props = extend({ name: this.name }, this);
+  // Allow errors to be converted to JSON for static transfer.
+  toJSON(stack: boolean): Record<string, unknown> {
+    const {...props} = this
 
     // include stack if exists and not turned off
     if (false !== stack && this.stack) {
       props.stack = this.stack;
     }
+    props.message = this.message
 
     return props;
   };

tsconfig.json

@@ -12,5 +12,5 @@
   },
   "include": [
     "src"
-]
+  ]
 }