operator

Functional operators

npm install operator
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operator.js

Functional operators for JavaScript, both client- and server-friendly.

Installation

Client-side, you need only include the latest version of the operator.js file in your page (download or link); this will add a single global operator to window.

You're also covered if you're using something like require.js or browserify to load your modules. Operator knows the module dance, and will check all of exports, module, and define so it can do the right thing.

For usage in node.js, install it via npm:

npm install operator

...And then require it:

var op = require('operator');

API

Contents

A few Brief Notes

  • Everything lives in one namespace. I typically require it as op; when no module systems are present, it lives in a global named operator.
  • Throughout this API, I use "defined" to mean x != null (which is equivalent to typeof x !== 'undefined' && x !== null).
  • In progress! Use the source, Luke.

Value Operators

Operators which do nothing other than return a value.

I(x) -> x

Identity operator.

K(k) -> -> k

Constant operator: returns a function which returns k.

nop()

noop()

No-op operator (technically returns undefined).

kThis() -> this

Returns the current context of execution (this).

kObject() -> {}

Returns a new object.

kArray() -> []

Returns a new array.

val(def,o)

Returns o if defined, def otherwise.

Test Operators

ok(o) -> Boolean

True if o is defined.

notOk(o) -> Boolean

True if o is not defined.

isK(k) -> (v) -> k === v

Returns a function which tests if its argument is equal to k.

Arity Operators

Operators which deal with arguments to functions.

second(_,a) -> a

Returns the second argument.

nth(n)

Returns the n-th argument.

flip(fn) -> Function

Returns a function that applies fn with whatever arguments it gets, but swapping the first two:

op.flip(fn)(a, b, c) === fn(b, a, c)

aritize(fn, [cxt], n)

Returns a function that applies fn, but limited to n arguments:

op.aritize(fn, 1)(a, b, c) === fn(a)

it(fn, [cxt])

Returns a function that applies fn, but limited to one argument (the same as op.aritize(fn, 1), but slightly faster):

op.it(fn)(a, b, c) === fn(a)

Accessor Operators

khas(k,o)

kget(k,o)

defkget(def,k,o)

thisget(k)

vkset(o,v,k)

has(o,k)

get(o,k)

getdef(o,k,def)

kvset(o,k,v)

thiskvset(k,v)

prop(k)

method(name, ...args)

parseBool(s)

toBool(s)

toInt(v)

toFloat(v)

toStr(v)

toRegExp(v)

toObject(v)

toDate(v)

Inequality Operators

cmp(x,y) -> if x < y then -1 else (if x > y then 1 else 0)

eq(x,y) -> x == y

ne(x,y) -> x != y

gt(x,y) -> x > y

ge(x,y) -> x >= y

lt(x,y) -> x < y

le(x,y) -> x <= y

Mathematical Operators

add(x,y) -> x + y

sub(x,y) -> x - y

mul(x,y) -> x * y

div(x,y) -> x / y

flrdiv(x,y) -> Math.floor(x / y)

mod(x,y) -> x % y

neg(x) -> -x

log2(n)

Log base-2.

Logical Operators

is(x,y) -> x is y

isnt(x,y) -> x is not y

and(x,y) -> x and y

or(x,y) -> x or y

not(x) -> not x

Bitwise Operators

bitnot(x) -> ~x

bitand(x,y) -> x & y

bitor(x,y) -> x | y

bitxor(x,y) -> x ^ y

lshift(x,y) -> x << y

rshift(x,y) -> x >> y

bin(n)

binlen(n)

mask(n)

chr(s)

ord(s)

encode(s)

decode(s)

strip(s)

Feedback

Find a bug or want to contribute? Open a ticket (or fork the source!) on github. You're also welcome to send me email at dsc@less.ly.

License

operator.js was written by David Schoonover (in Coco, a dialect of CoffeeScript that compiles down to JavaScript). It is open-source software and freely available under the MIT License.

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