could-be-class - npm Package Compare versions

Comparing version 0.1.4 to 0.2.0

index.d.ts

 /**
  * Checks if an object could be an instantiable class.
- * @param strict If `true`, when testing ES5 class, will check if its name's 
- *  first character is upper-cased.
  */
-export function isClass(obj: any, strict?: boolean): boolean;
+export function isClass(obj: any): obj is new (...args: any[]) => any;
 export default isClass;

index.js

@@ -0,33 +1,50 @@
+"use strict";
+
 /**
  * Checks if an object could be an instantiable class.
  * @param {any} obj
- * @param {boolean} strict
- * @returns {boolean}
+ * @returns {obj is new (...args: any[]) => any}
  */
-function couldBeClass(obj, strict) {
+function couldBeClass(obj) {
     if (typeof obj != "function") return false;
 
-    var str = obj.toString();
-    
     // async function or arrow function
-    if (obj.prototype === undefined) return false;
-    // generator function and malformed extends
-    if (obj.prototype.constructor !== obj) return false;
-     // ES6 class
-    if (str.slice(0, 5) == "class") return true;
+    if (obj.prototype === undefined)
+        return false;
+
+    // generator function and malformed inheritance
+    if (obj.prototype.constructor !== obj)
+        return false;
+
     // has own prototype properties
-    if (Object.getOwnPropertyNames(obj.prototype).length >= 2) return true;
+    if (Object.getOwnPropertyNames(obj.prototype).length >= 2)
+        return true;
+
+    var str = String(obj);
+
+    // ES6 class
+    if (str.slice(0, 5) == "class")
+        return true;
+
     // anonymous function
-    if (/^function\s+\(|^function\s+anonymous\(/.test(str)) return false;
-    // ES5 class without `this` in the body and the name's first character 
-    // upper-cased.
-    if (strict && /^function\s+[A-Z]/.test(str)) return true;
-     // has `this` in the body
-    if (/\b\(this\b|\bthis[\.\[]\b/.test(str)) {
-        // not strict or ES5 class generated by babel
-        if (!strict || /classCallCheck\(this/.test(str)) return true;
+    if (/^function\s*\(|^function anonymous\(/.test(str))
+        return false;
 
-        return /^function\sdefault_\d+\s*\(/.test(str);
+    var hasThis = /(call|apply|_classCallCheck)\(this(, arguments)?\)|\bthis(.\S+|\[.+?\])\s*(=|\()|=\s*this[,;]/.test(str);
+
+    // Upper-cased first char of the name and has `this` in the body, or it's
+    // a native class in ES5 style.
+    if (/^function\s+[A-Z]/.test(str) && (hasThis ||
+        (/\[native code\]/.test(str) &&
+            obj.name !== "BigInt" && // ES6 BigInt and Symbol is not class
+            obj.name !== "Symbol"
+        )
+    )) {
+        return true;
     }
 
+    // TypeScript anonymous class to ES5 with default export
+    if (hasThis && obj.name === "default_1")
+        return true;
+
     return false;
@@ -34,0 +51,0 @@ }

package.json

 {
   "name": "could-be-class",
-  "version": "0.1.4",
+  "version": "0.2.0",
   "description": "Checks if an object could be an instantiable class.",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -57,11 +57,6 @@ # couldBeClass
 
-function IsClass() {
-    console.log("this is a class");
-}
-assert.ok(couldBeClass(IsClass, true)); // strict mode
-
 function aMethod() {
     this.desc = "this is a method instead of a class";
 }
-assert.ok(!couldBeClass(aMethod, true)); // strict mode
+assert.ok(!couldBeClass(aMethod));
 
@@ -72,3 +67,2 @@ function default_1() {
 assert.ok(couldBeClass(default_1));
-assert.ok(couldBeClass(default_1, true)); // even in strict mode
 
@@ -79,3 +73,2 @@ function default_2() {
 assert.ok(!couldBeClass(default_2));
-assert.ok(!couldBeClass(default_2, true)); // even in strict mode
 
@@ -106,9 +99,3 @@ function* GenFunc() {
 
-**Strict Mode**, you can pass the second argument `strict: boolean` to the 
-function, if it is `true`, when testing ES5 class, will check if its name's 
-first character is upper-cased, which is the common and recommended way to 
-define a class. It always better to use the `strict` mode and code your classes 
-in the recommended way.
-
 **WARN** This module only performs about 98% percent of accuracy when testing 
 ES5 class.

test.js

@@ -26,3 +26,3 @@ "use strict";
 function D() { }
-D.prototype.show = function () { }
+D.prototype.show = function () { };
 assert.ok(couldBeClass(D));
@@ -59,12 +59,23 @@
 
+function aMethod() {
+    this.desc = "this is a method instead of a class";
+}
+assert.ok(!couldBeClass(aMethod));
+
+function NotClass2() {
+    // this. is nor a class.
+}
+assert.ok(!couldBeClass(NotClass2));
+
 function IsClass() {
-    console.log("this is a class");
+    this.doSomething();
 }
-assert.ok(couldBeClass(IsClass, true)); // strict mode
+assert.ok(couldBeClass(IsClass));
 
-function aMethod() {
-    this.desc = "this is a method instead of a class";
+function IsClass2() {
+    this.doSomething = () => {};
 }
-assert.ok(!couldBeClass(aMethod, true)); // strict mode
+assert.ok(couldBeClass(IsClass2));
 
+
 function default_1() {
@@ -74,3 +85,2 @@ this.dec = "this might be a class generated by typescript";
 assert.ok(couldBeClass(default_1));
-assert.ok(couldBeClass(default_1, true)); // even in strict mode
 
@@ -81,3 +91,2 @@ function default_2() {
 assert.ok(!couldBeClass(default_2));
-assert.ok(!couldBeClass(default_2, true)); // even in strict mode
 
@@ -84,0 +93,0 @@ function* GenFunc() {

No alert changes

Improved metrics

Lines of code

136

increased by11.48%

Worsened metrics

Total package byte prevSize

8439

decreased by-5.25%

Number of lines in readme file

97

decreased by-11.82%

No dependency changes