implement Array.prototype.findIndex. closes #456 (#457)

endel · Perryvw · commit 5bb7a0b0bf4f · 2019-02-26T20:28:45.000+01:00
* implement Array.prototype.findIndex. closes #456 * refactor findIndex method, add more test cases
diff --git a/src/LuaLib.ts b/src/LuaLib.ts
@@ -6,6 +6,7 @@ export enum LuaLibFeature {
     ArrayEvery = "ArrayEvery",
     ArrayFilter = "ArrayFilter",
     ArrayForEach = "ArrayForEach",
+    ArrayFindIndex = "ArrayFindIndex",
     ArrayIndexOf = "ArrayIndexOf",
     ArrayMap = "ArrayMap",
     ArrayPush = "ArrayPush",
diff --git a/src/LuaTransformer.ts b/src/LuaTransformer.ts
@@ -3724,6 +3724,8 @@ export class LuaTransformer {
                 );
             case "forEach":
                 return this.transformLuaLibFunction(LuaLibFeature.ArrayForEach, node, caller, ...params);
+            case "findIndex":
+                return this.transformLuaLibFunction(LuaLibFeature.ArrayFindIndex, node, caller, ...params);
             case "indexOf":
                 return this.transformLuaLibFunction(LuaLibFeature.ArrayIndexOf, node, caller, ...params);
             case "map":
diff --git a/src/lualib/ArrayFindIndex.ts b/src/lualib/ArrayFindIndex.ts
@@ -0,0 +1,11 @@
+function __TS__ArrayFindIndex<T>(
+    arr: T[],
+    callbackFn: (this: void, element: T, index?: number, array?: T[]) => boolean
+): number {
+    for (let i = 0, len = arr.length; i < len; i++) {
+        if (callbackFn(arr[i], i, arr)) {
+            return i;
+        }
+    }
+    return -1;
+}
diff --git a/test/unit/lualib/lualib.spec.ts b/test/unit/lualib/lualib.spec.ts
@@ -21,6 +21,39 @@ export class LuaLibTests
         Expect(result).toBe(JSON.stringify(expected));
     }
 
+    @TestCase([], 3, -1)
+    @TestCase([0, 2, 4, 8], 10, -1)
+    @TestCase([0, 2, 4, 8], 8, 3)
+    @Test("array.findIndex[value]")
+    public findIndexByValue(inp: number[], searchEl: number, expected: number): void
+    {
+        const result = util.transpileAndExecute(
+            `let arrTest = ${JSON.stringify(inp)};
+            return JSONStringify(arrTest.findIndex((elem, index) => {
+                return elem === ${searchEl};
+            }));`
+        );
+
+        // Assert
+        Expect(result).toBe(expected);
+    }
+
+    @TestCase([0, 2, 4, 8], 3, 8)
+    @TestCase([0, 2, 4, 8], 1, 2)
+    @Test("array.findIndex[index]")
+    public findIndexByIndex(inp: number[], expected: number, value: number): void
+    {
+        const result = util.transpileAndExecute(
+            `let arrTest = ${JSON.stringify(inp)};
+            return JSONStringify(arrTest.findIndex((elem, index, arr) => {
+                return index === ${expected} && arr[${expected}] === ${value};
+            }));`
+        );
+
+        // Assert
+        Expect(result).toBe(expected);
+    }
+
     @TestCase([], "x => x")
     @TestCase([0, 1, 2, 3], "x => x")
     @TestCase([0, 1, 2, 3], "x => x*2")
