forked from helpers/handlebars-helpers
/
math.js
226 lines (200 loc) · 4.19 KB
/
math.js
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'use strict';
const isNumber = require('lodash/isNumber');
const helpers = module.exports;
/**
* Return the magnitude of `a`.
*
* @param {Number} `a`
* @return {Number}
* @api public
*/
helpers.abs = function(num) {
if (!isNumber(num)) {
throw new TypeError('expected a number');
}
return Math.abs(num);
};
/**
* Return the sum of `a` plus `b`.
*
* @param {Number} `a`
* @param {Number} `b`
* @return {Number}
* @api public
*/
helpers.add = function(a, b) {
if (isNumber(a) && isNumber(b)) {
return a + b;
}
if (typeof a === 'string' && typeof b === 'string') {
return a + b;
}
return '';
};
/**
* Returns the average of all numbers in the given array.
*
* ```handlebars
* {{avg "[1, 2, 3, 4, 5]"}}
* <!-- results in: '3' -->
* ```
*
* @param {Array} `array` Array of numbers to add up.
* @return {Number}
* @api public
*/
helpers.avg = function() {
const args = [].concat.apply([], arguments);
// remove handlebars options object
args.pop();
return helpers.sum(args) / args.length;
};
/**
* Get the `Math.ceil()` of the given value.
*
* @param {Number} `value`
* @return {Number}
* @api public
*/
helpers.ceil = function(num) {
if (!isNumber(num)) {
throw new TypeError('expected a number');
}
return Math.ceil(num);
};
/**
* Divide `a` by `b`
*
* @param {Number} `a` numerator
* @param {Number} `b` denominator
* @api public
*/
helpers.divide = function(a, b) {
if (!isNumber(a)) {
throw new TypeError('expected the first argument to be a number');
}
if (!isNumber(b)) {
throw new TypeError('expected the second argument to be a number');
}
return a / b;
};
/**
* Get the `Math.floor()` of the given value.
*
* @param {Number} `value`
* @return {Number}
* @api public
*/
helpers.floor = function(num) {
if (!isNumber(num)) {
throw new TypeError('expected a number');
}
return Math.floor(num);
};
/**
* Return the product of `a` times `b`.
*
* @param {Number} `a` factor
* @param {Number} `b` multiplier
* @return {Number}
* @api public
*/
helpers.multiply = function(a, b) {
if (!isNumber(a)) {
throw new TypeError('expected the first argument to be a number');
}
if (!isNumber(b)) {
throw new TypeError('expected the second argument to be a number');
}
return a * b;
};
/**
* Generate a random number between two values
*
* @param {Number} `min`
* @param {Number} `max`
* @return {Number}
* @api public
*/
helpers.random = function(min, max) {
if (!isNumber(min)) {
throw new TypeError('expected minimum to be a number');
}
if (!isNumber(max)) {
throw new TypeError('expected maximum to be a number');
}
return min + Math.floor(Math.random() * (max - min + 1));
};
/**
* Get the remainder of dividing `a` by `b`.
*
* ```handlebars
* {{remainder 7 5}}
* <!-- results in: 2 -->
* ```
* @param {Number} `a`
* @param {Number} `b`
* @return {Number}
* @api public
*/
helpers.remainder = function(a, b) {
if (!isNumber(a)) {
throw new TypeError('expected the first argument to be a number');
}
if (!isNumber(b)) {
throw new TypeError('expected the second argument to be a number');
}
return a % b;
};
/**
* Round the given number.
*
* @param {Number} `number`
* @return {Number}
* @api public
*/
helpers.round = function(num) {
if (!isNumber(num)) {
throw new TypeError('expected a number');
}
return Math.round(num);
};
/**
* Return the product of `a` minus `b`.
*
* @param {Number} `a`
* @param {Number} `b`
* @return {Number}
* @api public
*/
helpers.subtract = function(a, b) {
if (!isNumber(a)) {
throw new TypeError('expected the first argument to be a number');
}
if (!isNumber(b)) {
throw new TypeError('expected the second argument to be a number');
}
return a - b;
};
/**
* Returns the sum of all numbers in the given array.
*
* ```handlebars
* {{sum "[1, 2, 3, 4, 5]"}}
* <!-- results in: '15' -->
* ```
* @param {Array} `array` Array of numbers to add up.
* @return {Number}
* @api public
*/
helpers.sum = function() {
const args = [].concat.apply([], arguments);
let len = args.length;
let sum = 0;
while (len--) {
if (isNumber(args[len])) {
sum += Number(args[len]);
}
}
return sum;
};