feat(arrays): add find/findIndex()

thi-ng · Feb 14, 2019 · 0007152 · 0007152
1 parent 51959b7
commit 0007152
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diff --git a/packages/arrays/src/find.ts b/packages/arrays/src/find.ts
@@ -0,0 +1,32 @@
+import { Predicate2 } from "@thi.ng/api";
+import { equiv as _equiv } from "@thi.ng/equiv";
+
+/**
+ * Similar to `Array.find()`, but uses thi.ng/equiv as default
+ * predicate.
+ *
+ * @param src
+ * @param x
+ * @param equiv
+ */
+export const find =
+    <T>(src: ArrayLike<T>, x: T, equiv: Predicate2<T> = _equiv) => {
+        const i = findIndex(src, x, equiv);
+        return i !== -1 ? src[i] : undefined;
+    };
+
+/**
+ * Similar to `Array.findIndex()`, but uses thi.ng/equiv as default
+ * predicate.
+ *
+ * @param src
+ * @param x
+ * @param equiv
+ */
+export const findIndex =
+    <T>(src: ArrayLike<T>, x: T, equiv: Predicate2<T> = _equiv) => {
+        for (let i = src.length; --i >= 0;) {
+            if (equiv(x, src[i])) return i;
+        }
+        return -1;
+    };
diff --git a/packages/arrays/src/index.ts b/packages/arrays/src/index.ts
@@ -2,6 +2,7 @@ export * from "./binary-search";
 export * from "./ends-with";
 export * from "./ensure-array";
 export * from "./ensure-iterable";
+export * from "./find";
 export * from "./fuzzy-match";
 export * from "./peek";
 export * from "./shuffle";