lib: cleanup instance validation

Cleaned up the `URLSearchParams`'s `this` validation to increase
readability by moving them to an extra helper function.

PR-URL: #39656
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Darshan Sen <raisinten@gmail.com>

lib/internal/url.js

@@ -179,6 +179,10 @@ class URLContext {
   }
 }
 
+function isURLSearchParams(self) {
+  return self && self[searchParams] && !self[searchParams][searchParams];
+}
+
 class URLSearchParams {
   // URL Standard says the default value is '', but as undefined and '' have
   // the same result, undefined is used to prevent unnecessary parsing.
@@ -248,9 +252,8 @@ class URLSearchParams {
   }
 
   [inspect.custom](recurseTimes, ctx) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
 
     if (typeof recurseTimes === 'number' && recurseTimes < 0)
       return ctx.stylize('[Object]', 'special');
@@ -285,9 +288,9 @@ class URLSearchParams {
   }
 
   append(name, value) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     if (arguments.length < 2) {
       throw new ERR_MISSING_ARGS('name', 'value');
     }
@@ -299,9 +302,9 @@ class URLSearchParams {
   }
 
   delete(name) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     if (arguments.length < 1) {
       throw new ERR_MISSING_ARGS('name');
     }
@@ -320,9 +323,9 @@ class URLSearchParams {
   }
 
   get(name) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     if (arguments.length < 1) {
       throw new ERR_MISSING_ARGS('name');
     }
@@ -338,9 +341,9 @@ class URLSearchParams {
   }
 
   getAll(name) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     if (arguments.length < 1) {
       throw new ERR_MISSING_ARGS('name');
     }
@@ -357,9 +360,9 @@ class URLSearchParams {
   }
 
   has(name) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     if (arguments.length < 1) {
       throw new ERR_MISSING_ARGS('name');
     }
@@ -375,9 +378,9 @@ class URLSearchParams {
   }
 
   set(name, value) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     if (arguments.length < 2) {
       throw new ERR_MISSING_ARGS('name', 'value');
     }
@@ -462,17 +465,16 @@ class URLSearchParams {
   // Define entries here rather than [Symbol.iterator] as the function name
   // must be set to `entries`.
   entries() {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
 
     return createSearchParamsIterator(this, 'key+value');
   }
 
   forEach(callback, thisArg = undefined) {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
+
     validateCallback(callback);
 
     let list = this[searchParams];
@@ -490,27 +492,24 @@ class URLSearchParams {
 
   // https://heycam.github.io/webidl/#es-iterable
   keys() {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
 
     return createSearchParamsIterator(this, 'key');
   }
 
   values() {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
 
     return createSearchParamsIterator(this, 'value');
   }
 
   // https://heycam.github.io/webidl/#es-stringifier
   // https://url.spec.whatwg.org/#urlsearchparams-stringification-behavior
   toString() {
-    if (!this || !this[searchParams] || this[searchParams][searchParams]) {
+    if (!isURLSearchParams(this))
       throw new ERR_INVALID_THIS('URLSearchParams');
-    }
 
     return serializeParams(this[searchParams]);
   }