Exports validation (#4)

README.md

@@ -84,6 +84,25 @@ const result = moveMultiIndex(input, FromToObj);
 // result = ["a", "c", "a"];
 ```
 
+Validation function is also exported:
+
+`isValid(array, { from, to })` and it returns `false` when:
+
+- input is not array
+- input array is empty
+- from/to is out of range
+- from/to is not numbers
+
+```js
+isValid([1, 2, 3], { from: 0, to: 1 });
+
+// true
+
+isValid([1, 2, 3], { from: 10, to: 1 });
+
+// false
+```
+
 ## Tests
 
 ```sh

index.js

@@ -6,10 +6,11 @@
  * @param {number} to - targeted index
  * @returns
  */
-function isNotInRange(arr, from, to) {
+function isNotInRange(arr, { from, to } = {}) {
   const { length } = arr;
 
   return (
+    !Array.isArray(arr) ||
     typeof from !== "number" ||
     typeof to !== "number" ||
     from < 0 ||
@@ -19,6 +20,10 @@ function isNotInRange(arr, from, to) {
   );
 }
 
+function isValid(arr, form2Obj) {
+  return !isNotInRange.call(this, arr, form2Obj);
+}
+
 /**
  * Moves element form/to index.
  *
@@ -29,7 +34,7 @@ function isNotInRange(arr, from, to) {
  * @returns {Array}
  */
 function move(arr = [], from, to, isMutate = true) {
-  if (isNotInRange(arr, from, to)) return arr;
+  if (isNotInRange(arr, { from, to })) return arr;
 
   const modified = isMutate ? arr : arr.slice();
 
@@ -48,7 +53,7 @@ function move(arr = [], from, to, isMutate = true) {
  * @returns {Array}
  */
 function moveMultiArr(multiArr, from, to, isMutate) {
-  return multiArr.map(arr => move(arr, from, to, isMutate));
+  return multiArr.map((arr) => move(arr, from, to, isMutate));
 }
 
 /**
@@ -69,7 +74,8 @@ function moveMultiIndex(arr = [], movingMap) {
 }
 
 module.exports = {
+  isValid,
   move,
   moveMultiArr,
-  moveMultiIndex
+  moveMultiIndex,
 };

test.js

@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const { expect } = require("chai");
 
-const { move, moveMultiArr, moveMultiIndex } = require("./index");
+const { move, moveMultiArr, moveMultiIndex, isValid } = require("./index");
 
 describe("move-position", () => {
   it("returns the same input when params is invalid", () => {
@@ -92,3 +92,43 @@ describe("move-position", () => {
     expect(result).to.have.deep.members(expected);
   });
 });
+
+describe("tests validation", () => {
+  describe("detects invalid returns false:", () => {
+    it("when not array", () => {
+      const result = isValid("foo");
+      expect(result).to.be.equal(false);
+    });
+
+    it("when array is empty", () => {
+      const result = isValid([]);
+      expect(result).to.be.equal(false);
+    });
+
+    it("when from/to is out of range", () => {
+      let result = isValid([1, 2, 3], { from: -4, to: 0 });
+      expect(result).to.be.equal(false);
+
+      result = isValid([1, 2, 3], { from: 4, to: 0 });
+      expect(result).to.be.equal(false);
+
+      result = isValid([1, 2, 3], { from: 1, to: 6 });
+      expect(result).to.be.equal(false);
+
+      result = isValid([1, 2, 3], { from: 1, to: -6 });
+      expect(result).to.be.equal(false);
+    });
+
+    it("when from/to is not numbers", () => {
+      const result = isValid([1, 2, 3], { from: "1", to: "0" });
+      expect(result).to.be.equal(false);
+    });
+  });
+
+  describe("detects valid returns true:", () => {
+    it("when valid array", () => {
+      const result = isValid([1, 2, 3], { from: 0, to: 1 });
+      expect(result).to.be.equal(true);
+    });
+  });
+});