Add custom type assertions for goog.is* functions.

Fixes angular#710
ribrdb · May 29, 2019 · 3cdae25 · 3cdae25
1 parent 6c8a2bd
commit 3cdae25
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Showing 4 changed files with 111 additions and 5 deletions.
diff --git a/src/main/java/com/google/javascript/clutz/DeclarationGenerator.java b/src/main/java/com/google/javascript/clutz/DeclarationGenerator.java
@@ -2950,6 +2950,47 @@ private boolean isTemplateOf(JSType type, String typeName) {
           && type.toMaybeTemplatizedType().getReferenceName().equals(typeName);
     }
 
+    private boolean handleSpecialTypeAssertionFunctions(String propName) {
+      if (!isGoogNamespace) return false;
+      if (propName.equals("isArray")) {
+        emit("(val : any ) : val is any[] ");
+        return true;
+      }
+      if (propName.equals("isBoolean")) {
+        emit("(val : any ) : val is boolean ");
+        return true;
+      }
+      if (propName.equals("isDef")) {
+        emit("<T> (val : T ) : val is Exclude<T, undefined> ");
+        return true;
+      }
+      if (propName.equals("isDefAndNotNull")) {
+        emit("<T> (val : T ) : val is NonNullable<T> ");
+        return true;
+      }
+      if (propName.equals("isFunction")) {
+        emit("(val : any ) : val is Function ");
+        return true;
+      }
+      if (propName.equals("isNull")) {
+        emit("(val : any ) : val is null ");
+        return true;
+      }
+      if (propName.equals("isNumber")) {
+        emit("(val : any ) : val is number ");
+        return true;
+      }
+      if (propName.equals("isObject")) {
+        emit("(val : any ) : val is Object ");
+        return true;
+      }
+      if (propName.equals("isString")) {
+        emit("(val : any ) : val is string ");
+        return true;
+      }
+      return false;
+    }
+
     /**
      * Closure has an experimental feature - Type Transformation Expression (TTE) - used to type
      * functions like Promise.then and Promise.all. The feature is rarely used and impossible to
@@ -3384,7 +3425,8 @@ void walkInnerSymbols(ObjectType type, String innerNamespace) {
     private void visitFunctionExpression(String propName, FunctionType ftype) {
       emit("function");
       emit(propName);
-      visitFunctionDeclaration(ftype, Collections.<String>emptyList());
+      if (!handleSpecialTypeAssertionFunctions(propName))
+        visitFunctionDeclaration(ftype, Collections.<String>emptyList());
       emit(";");
       emitBreak();
     }

diff --git a/src/test/java/com/google/javascript/clutz/base.d.ts b/src/test/java/com/google/javascript/clutz/base.d.ts
@@ -20,7 +20,15 @@ declare namespace goog {
    */
   function exportProperty (object : ಠ_ಠ.clutz.GlobalObject | null , publicName : string , symbol : any ) : void ;
   function inherits (childCtor : Function , parentCtor : Function ) : void ;
-  function isDef (val : any ) : boolean ;
+  function isArray (val : any ) : val is any[]  ;
+  function isBoolean (val : any ) : val is boolean  ;
+  function isDef <T> (val : T ) : val is Exclude<T, undefined>  ;
+  function isDefAndNotNull <T> (val : T ) : val is NonNullable<T>  ;
+  function isFunction (val : any ) : val is Function  ;
+  function isNull (val : any ) : val is null  ;
+  function isNumber (val : any ) : val is number  ;
+  function isObject (val : any ) : val is Object  ;
+  function isString (val : any ) : val is string  ;
   function require (name : string ) : ಠ_ಠ.clutz.ClosureSymbolNotGoogProvided;
   let /**
    * Reference to the global context.  In most cases this will be 'window'.

diff --git a/src/test/java/com/google/javascript/clutz/base.js b/src/test/java/com/google/javascript/clutz/base.js
@@ -36,11 +36,59 @@ goog.require = function(name) {};
 goog.inherits = function(childCtor, parentCtor) {};
 
 /**
- * @param {?} val Variable to test.
- * @return {boolean} Whether variable is defined.
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isArray = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isBoolean = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
  */
 goog.isDef = function(val) {};
 
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isDefAndNotNull = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isFunction = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isNull = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isNumber = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isObject = function(val) {};
+
+/**
+ * @param {?} val
+ * @return {boolean}
+ */
+goog.isString = function(val) {};
+
 goog.provide('goog.Uri');
 /** @constructor */
 goog.Uri =  function() {}

diff --git a/src/test/java/com/google/javascript/clutz/outputBase/function_alias_output_base.d.ts b/src/test/java/com/google/javascript/clutz/outputBase/function_alias_output_base.d.ts
@@ -20,7 +20,15 @@ declare namespace goog {
    */
   function exportProperty (object : ಠ_ಠ.clutz.GlobalObject | null , publicName : string , symbol : any ) : void ;
   function inherits (childCtor : ಠ_ಠ.clutz.partial.FunctionAlias , parentCtor : ಠ_ಠ.clutz.partial.FunctionAlias ) : void ;
-  function isDef (val : any ) : boolean ;
+  function isArray (val : any ) : val is any[]  ;
+  function isBoolean (val : any ) : val is boolean  ;
+  function isDef <T> (val : T ) : val is Exclude<T, undefined>  ;
+  function isDefAndNotNull <T> (val : T ) : val is NonNullable<T>  ;
+  function isFunction (val : any ) : val is Function  ;
+  function isNull (val : any ) : val is null  ;
+  function isNumber (val : any ) : val is number  ;
+  function isObject (val : any ) : val is Object  ;
+  function isString (val : any ) : val is string  ;
   function require (name : string ) : ಠ_ಠ.clutz.ClosureSymbolNotGoogProvided;
   let /**
    * Reference to the global context.  In most cases this will be 'window'.