fix(setpos): fix a boundry contion for setPos

Author: paradite

README.md

@@ -16,12 +16,21 @@ $ yarn add numeric-array-integer
 ## Usage:
 
 ```js
+// Initialize new NumericArrayInteger with bits per number 4 (max number is 2^4-1, 15), total bit length 10
 const integer = new NumericArrayInteger(4, 10);
+
+// Set number at position
 integer.setPos(0, 3);
 integer.setPos(2, 2);
+
+// Get data as an integer
 const data = integer.getData();
 console.log(data); // 515
+
+// Load data from an integer
 const integer2 = NumericArrayInteger.fromData(data, 4, 10);
+
+// Get back original number at position
 console.log(integer2.getPos(0)); // 3
 console.log(integer2.getPos(2)); // 2
 ```

package.json

@@ -1,6 +1,6 @@
 {
   "name": "numeric-array-integer",
-  "version": "3.0.0",
+  "version": "3.1.0",
   "description": "JavaScript numeric array implemented using an integer",
   "main": "dist/index.js",
   "module": "./dist/index.mjs",

src/index.ts

@@ -50,7 +50,7 @@ export class NumericArrayInteger {
     if (position > this.arrayLength) {
       throw new Error('Position exceeds length');
     }
-    if (value > 2 ** this.elementBitLength) {
+    if (value >= 2 ** this.elementBitLength) {
       throw new Error('Value exceeds bit length');
     }
     const mask = value << (position * this.elementBitLength);

test/index.test.ts

@@ -32,9 +32,14 @@ describe('NumericArrayInteger', () => {
     expect(() => integer.clearPos(13)).toThrowError('Position exceeds length');
   });
 
-  it('set position throw error for invalid value', () => {
+  it('set position handle boundry and invalid value', () => {
     const integer = new NumericArrayInteger(4, 10);
-    expect(() => integer.setPos(1, 17)).toThrowError(
+    integer.setPos(1, 2 ** 4 - 1);
+    expect(integer.getPos(1)).toEqual(2 ** 4 - 1);
+    expect(() => integer.setPos(1, 2 ** 4 + 1)).toThrowError(
+      'Value exceeds bit length'
+    );
+    expect(() => integer.setPos(1, 2 ** 4)).toThrowError(
       'Value exceeds bit length'
     );
   });