time-to-botec/js/node_modules/@stdlib/utils/compose/README.md

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# compose

> [Function composition][function-composition].

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</section>

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## Usage

```javascript
var compose = require( '@stdlib/utils/compose' );
```

#### compose( ...fcn )

Returns a composite function. Starting from the right, the composite function evaluates each function and passes the result as an argument to the next function. The result of the leftmost function is the result of the whole.

```javascript
function a( x ) {
    return 2 * x;
}

function b( x ) {
    return x + 3;
}

function c( x ) {
    return x / 5;
}

var f = compose( c, b, a );

var z = f( 6 ); // ((2*x)+3)/5
// returns 3
```

**Only** the rightmost function is explicitly permitted to accept multiple arguments. All other functions are evaluated as **unary** functions.

```javascript
function a( x, y ) {
    return (x*5) + (y*3);
}

function b( r ) {
    return r + 12;
}

var f = compose( b, a );

var z = f( 4, 6 );
// returns 50
```

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## Notes

-   The function will throw if provided fewer than `2` input arguments.

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## Examples

<!-- eslint no-undef: "error" -->

```javascript
var compose = require( '@stdlib/utils/compose' );

function a( x, y ) {
    return x * y;
}

function b( z ) {
    return z + 5;
}

function c( r ) {
    return r / 10;
}

var f = compose( c, b, a );

var v = f( 5, 3 );
// returns 2
```

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[function-composition]: https://en.wikipedia.org/wiki/Function_composition_%28computer_science%29

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