mathjs/docs/reference/functions/chain.md

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

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# Function chain

Wrap any value in a chain, allowing to perform chained operations on
the value.

All methods available in the math.js library can be called upon the chain,
and then will be evaluated with the value itself as first argument.
The chain can be closed by executing `chain.done()`, which returns
the final value.

The chain has a number of special functions:

- `done()`     Finalize the chain and return the chain's value.
- `valueOf()`  The same as `done()`
- `toString()` Executes `math.format()` onto the chain's value, returning
               a string representation of the value.


## Syntax

```js
math.chain(value)
```

### Parameters

Parameter | Type | Description
--------- | ---- | -----------
`value` | * | A value of any type on which to start a chained operation.

### Returns

Type | Description
---- | -----------
math.Chain | The created chain


## Examples

```js
math.chain(3)
    .add(4)
    .subtract(2)
    .done()     // 5

math.chain( [[1, 2], [3, 4]] )
    .subset(math.index(0, 0), 8)
    .multiply(3)
    .done()     // [[24, 6], [9, 12]]
```