Merge pull request #69 from someyoungideas/isIntegers

initial commit implementing isIntegers

Author: jhowardjr

README.md

@@ -68,7 +68,7 @@ List of possible functions and their implementation status, compiled by [@D1esel
 General Types:
 
 - [ ] Natural numbers
-- [ ] Integers
+- [x] Integers
 - [ ] Rational numbers
 - [ ] Irrational numbers
 - [ ] Real numbers

index.js

@@ -16,6 +16,7 @@ module.exports = Object.assign(
   require('./lib/floatPrecise.js'),
   require('./lib/isAscending.js'),
   require('./lib/isDescending.js'),
+  require('./lib/isIntegers.js'),
   require('./lib/isPrime.js'),
   require('./lib/isComposit.js'),
   require('./lib/maximum.js'),

lib/isIntegers.js

@@ -0,0 +1,13 @@
+/**
+ * This function evaluates whether all parameters are integers
+ * @memberof variadic
+ * @author someyoungideas
+ * @param {...*} params - One or more parameters.
+ */
+exports.isIntegers = (...params) => {
+  if (params.length === 0) throw Error('Please provide at least one number to evaluate isInteger.');
+  if (params.some(param => Number.isNaN(Number.parseFloat(param)))) throw Error('Please provide all numbers to evaluate isInteger.');
+  if (params.some(param => !Number.isInteger(Number.parseFloat(param)))) return false;
+
+  return true;
+};

package-lock.json

@@ -0,0 +1,32 @@
+const { isIntegers } = require('../lib/isIntegers');
+
+describe('isIntegers', () => {
+  it('should throw an error if no parameters are provided', () => {
+    expect(() => isIntegers()).toThrow();
+  });
+
+  it('should throw an error if any parameters provided are not numbers', () => {
+    expect(() => isIntegers('')).toThrow();
+    expect(() => isIntegers('test', 2)).toThrow();
+  });
+
+  it('should return false if any parameters are not an integer', () => {
+    expect(isIntegers(2.5)).toBe(false);
+    expect(isIntegers(2, 2.5)).toBe(false);
+  });
+
+  it('should return true if all parameters are integers', () => {
+    expect(isIntegers(0)).toBe(true);
+    expect(isIntegers(2)).toBe(true);
+    expect(isIntegers(-1)).toBe(true);
+    expect(isIntegers(-1, 0, 2)).toBe(true);
+  });
+
+  it('should return true if all parameters can parse to integer', () => {
+    expect(isIntegers('0')).toBe(true);
+    expect(isIntegers('2')).toBe(true);
+    expect(isIntegers('-1')).toBe(true);
+    expect(isIntegers('-1', '0', '2')).toBe(true);
+    expect(isIntegers('-1', 0, '2')).toBe(true);
+  });
+});