@anthonypena/fp
v1.0.1
Published
Basic functional programming for TypeScript coders.
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Readme
@anthonypena/fp
Install
npm i @anthonypena/fp
Examples
Simple array filtering
import { isDefined, isDefinedAndNotEmpty, not } from '@anthonypena/fp';
const data = [
{ id: 'A', height: 10 },
{ id: 'B', name: 'B', height: 10 },
{ id: 'C', name: 'C', height: 12 },
{ id: 'C', name: '', height: 9 },
null
];
function isTall(x: { height: number }) {
return x.height > 10;
}
const res = data
.filter(isDefined)
.filter(not(isTall))
.map(x => x.name)
.filter(isDefinedAndNotEmpty);
// res = [ { id: 'B', name: 'B', height: 10 } ]
Docs
deepClone
This function will create a copy the passed value in most of the case.
Exception: undefined, null, number, boolean, Number.NEGATIVE_INFINITY, Number.POSITIVE_INFINITY
Parameters:
x
: any value
Exemples:
deepClone(1);
deepClone(Number.NEGATIVE_INFINITY);
deepClone('A');
deepClone({ a: 1 });
deepClone({ a: { b: 'C' } });
deepClone(['A']);
deepClone([[[['A']]]]);
identity
This function will return the first parameter.
Parameters:
x
: the first parameter
Exemples:
const res = identity(1); // res = 1
[1, 2, 3].map(identity); // [ 1, 2, 3 ]
isDifferent
This function compare two value of the same type.
Parameters:
a
: one valueb
: another value
Exemples:
isDifferent(1,1) // false
isDifferent(1,2) // true
isDifferent({ a: 'A' }, { a: 'A' }) // false
isDifferent({ a: 'A' }, { a: 'B' }) // true
Note: opposite of
isEqual
isDefined
This function check passed value is defined with correct TypeScript type assertion.
Parameters:
x
: one value which may be undefined or null
Exemples:
isDefined(1) // true
isDefined('A') // true
isDefined({ a: 'A' }) // true
isDefined([]) // true
isDefined(undefined) // false
isDefined(null) // false
isDefinedAndNotEmpty
This function check passed value is defined and is not empty with correct TypeScript type assertion.
Parameters:
x
: one value which have a length and may be undefined or null
Exemples:
isDefinedAndNotEmpty('') // false
isDefinedAndNotEmpty('A') // true
isDefinedAndNotEmpty([]) // false
isDefinedAndNotEmpty(['A']) // true
isDefinedAndNotEmpty(undefined) // false
isDefinedAndNotEmpty(null) // false
isEmpty
This function check if passed value is empty with correct TypeScript type assertion.
Parameters:
x
: one value which have a length
Exemples:
isEmpty([]) // true
isEmpty('') // true
isEmpty(['A']) // false
isEmpty('A') // false
isEqual
This function compare two value of the same type.
Parameters:
a
: one valueb
: another value
Exemples:
isEqual(1,1) // true
isEqual(1,2) // false
isEqual({ a: 'A' }, { a: 'A' }) // true
isEqual({ a: 'A' }, { a: 'B' }) // false
isNotDefined
This function check passed value is not defined with correct TypeScript type assertion.
Parameters:
x
: one value which may be undefined or null
Exemples:
isNotDefined(1) // false
isNotDefined('A') // false
isNotDefined({ a: 'A' }) // false
isNotDefined([]) // false
isNotDefined(undefined) // true
isNotDefined(null) // true
Note: opposite of
isDefined
isNotDefinedOrEmpty
This function check passed value is not defined or is empty with correct TypeScript type assertion.
Parameters:
x
: one value which have a length and may be undefined or null
Exemples:
isNotDefinedOrEmpty('') // true
isNotDefinedOrEmpty('A') // false
isNotDefinedOrEmpty([]) // true
isNotDefinedOrEmpty(['A']) // false
isNotDefinedOrEmpty(undefined) // true
isNotDefinedOrEmpty(null) // true
isNotEmpty
This function check if passed value is not empty with correct TypeScript type assertion.
Parameters:
x
: one value which have a length
Exemples:
isNotEmpty([]) // false
isNotEmpty('') // false
isNotEmpty(['A']) // true
isNotEmpty('A') // true
Note: opposite of
isEmpty
noop
This function do nothing.
Exemples:
noop();
[1, 2, 3].forEach(noop);
not
This function will negate the boolean value in parameter.
Parameters:
x
: a boolean value
Exemples:
not(true); // false
not(false); // true
notf
This function will negate the result of the function in parameter.
Parameters:
f
: a function which return boolean
Exemples:
[1,2,3].map(notf(isEven)); // [true, false, true]
// or
const isOdd = notf(isEven);
[1,2,3].map(isOdd); // [true, false, true]