Source

mathmethods.js /

Filename Size Date modified Message
spec
485 B
4.0 KB
868 B
1.5 KB
823 B
705 B

mathmethods.js

npm install mathmethods

mathmethods.js is a tiny script which makes methods of the Math object available to numbers by adding properties to Number.prototype. This makes it possible to write certain expressions in a more expressive (Ruby-like) manner.

For each Math method, a property is added to Number.prototype. Accessing one of these properties invokes the appropriate method with the number as the first argument. The majority of the Math methods take exactly one argument, so parentheses are not required.

// with mathmethods.js                    // without

dollars = balance.floor                   dollars = Math.floor(balance)

width = $nav.offset().left.abs            width = Math.abs($nav.offset().left)

Infinity.atan.log.sqrt                    Math.sqrt(Math.log(Math.atan(Infinity)))

A few Math methods – atan2, max, min, and pow – take more than one argument. When a property corresponding to one of these methods is accessed, a callable is returned which accepts the remaining arguments.

// with mathmethods.js                    // without

x.pow(y)                                  Math.pow(x, y)

fee = 0..max(rate * hours - advance)      fee = Math.max(0, rate * hours - advance)

kim.wage = 10..min(ian.wage, jan.wage)    kim.wage = Math.min(10, ian.wage, jan.wage)

random

Math.random takes zero arguments. For consistency with the other methods, Number.prototype.random produces a number between 0 and this. 100..random, for example, produces a number between 0 and 100.

// generate a number between 0 and 1 (inclusive of 0, exclusive of 1)

1..random                                 Math.random()

// simluate a die roll

6..random.floor + 1                       Math.floor(6 * Math.random()) + 1

squared and cubed

Shorthands for the equivalent .pows.

// with mathmethods.js                    // without

area = width.squared                      area = Math.pow(width, 2)

volume = x.cubed                          volume = Math.pow(x, 3)

Running the test suite

npm install
npm test

Internet Explorer

There's a bug in IE9 which breaks getters for number primitives which are integers. To accommodate IE9 one must work with Number objects exclusively.

// with mathmethods.js (IE9-safe)         // without

dollars = new Number(balance).floor       dollars = Math.floor(balance)

This introduces unacceptable noise. One can quieten it to a certain extent by defining a function which returns a Number object whose value is equivalent to that of the provided argument.

function _(n) { return new Number(n) }

// with mathmethods.js (IE9-safe)         // without

dollars = _(balance).floor                dollars = Math.floor(balance)

width = _($nav.offset().left).abs         width = Math.abs($nav.offset().left)

Infinity.atan.log.sqrt                    Math.sqrt(Math.log(Math.atan(Infinity)))

_(x).pow(y)                               Math.pow(x, y)

fee = _(0).max(rate * hours - advance)    fee = Math.max(0, rate * hours - advance)

kim.wage = _(10).min(ian.wage, jan.wage)  kim.wage = Math.min(10, ian.wage, jan.wage)

_(1).random                               Math.random()

_(6).random.floor + 1                     Math.floor(6 * Math.random()) + 1

area = _(width).squared                   area = Math.pow(width, 2)

volume = _(x).cubed                       volume = Math.pow(x, 3)

A better workaround would be extremely gratefully received!