# GC.Spread.CalcEngine.Functions.Function

## Content

# Class: Function

[CalcEngine](../modules/GC.Spread.CalcEngine).[Functions](../modules/GC.Spread.CalcEngine.Functions).Function

## Hierarchy

- **`Function`**

  ↳ [`AsyncFunction`](GC.Spread.CalcEngine.Functions.AsyncFunction)

## Table of contents

### Constructors

- [constructor](GC.Spread.CalcEngine.Functions.Function#constructor)

### Properties

- [maxArgs](GC.Spread.CalcEngine.Functions.Function#maxargs)
- [minArgs](GC.Spread.CalcEngine.Functions.Function#minargs)
- [name](GC.Spread.CalcEngine.Functions.Function#name)
- [typeName](GC.Spread.CalcEngine.Functions.Function#typename)

### Methods

- [acceptsArray](GC.Spread.CalcEngine.Functions.Function#acceptsarray)
- [acceptsError](GC.Spread.CalcEngine.Functions.Function#acceptserror)
- [acceptsMissingArgument](GC.Spread.CalcEngine.Functions.Function#acceptsmissingargument)
- [acceptsReference](GC.Spread.CalcEngine.Functions.Function#acceptsreference)
- [description](GC.Spread.CalcEngine.Functions.Function#description)
- [evaluate](GC.Spread.CalcEngine.Functions.Function#evaluate)
- [findBranchArgument](GC.Spread.CalcEngine.Functions.Function#findbranchargument)
- [findTestArgument](GC.Spread.CalcEngine.Functions.Function#findtestargument)
- [isBranch](GC.Spread.CalcEngine.Functions.Function#isbranch)
- [isContextSensitive](GC.Spread.CalcEngine.Functions.Function#iscontextsensitive)
- [isVolatile](GC.Spread.CalcEngine.Functions.Function#isvolatile)

## Constructors

### <a id="constructor" name="constructor"></a> constructor

• **new Function**(`name`, `minArgs?`, `maxArgs?`, `functionDescription?`)

Represents an abstract base class for defining functions.

**`example`**
```javascript
class FactorialFunction extends GC.Spread.CalcEngine.Functions.Function {
    constructor () {
        super('FACTORIAL', 1, 1, {
            description: "Function to calculate the Fibonacci number.",
            parameters: [{ name: 'n' }]
        });
    }
    evaluate (n) {
        var fib = [0, 1];
        for (var i = 2; i <= n; i++) {
          fib[i] = fib[i - 1] + fib[i - 2];
        }
        return fib[n];
    }
}
spread.addCustomFunction(new FactorialFunction());
spread.getActiveSheet().setFormula(0, 0, '=FACTORIAL(10)');
```

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `name` | `string` | The name of the function. |
| `minArgs?` | `number` | - |
| `maxArgs?` | `number` | - |
| `functionDescription?` | [`IFunctionDescription`](../interfaces/GC.Spread.CalcEngine.Functions.IFunctionDescription) | - |

## Properties

### <a id="maxargs" name="maxargs"></a> maxArgs

• **maxArgs**: `number`

Represents the maximum number of arguments for the function.

___

### <a id="minargs" name="minargs"></a> minArgs

• **minArgs**: `number`

Represents the minimum number of arguments for the function.

___

### <a id="name" name="name"></a> name

• **name**: `string`

Represents the name of the function.

___

### <a id="typename" name="typename"></a> typeName

• **typeName**: `string`

Represents the type name string used for supporting serialization.

## Methods

### <a id="acceptsarray" name="acceptsarray"></a> acceptsArray

▸ **acceptsArray**(`argIndex`): `boolean`

Determines whether the function accepts array values for the specified argument.

**`function`**

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `argIndex` | `number` | Index of the argument. |

#### Returns

`boolean`

`true` if the function accepts array values for the specified argument; otherwise, `false`.

___

### <a id="acceptserror" name="acceptserror"></a> acceptsError

▸ **acceptsError**(`argIndex`): `boolean`

Indicates whether the function can process Error values.

**`function`**

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `argIndex` | `number` | Index of the argument. |

#### Returns

`boolean`

`true` if the function can process Error values for the specified argument; otherwise, `false`.

___

### <a id="acceptsmissingargument" name="acceptsmissingargument"></a> acceptsMissingArgument

▸ **acceptsMissingArgument**(`argIndex`): `boolean`

Indicates whether the Evaluate method can process missing arguments.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `argIndex` | `number` | Index of the argument |

#### Returns

`boolean`

`true` if the Evaluate method can process missing arguments; otherwise, `false`.

___

### <a id="acceptsreference" name="acceptsreference"></a> acceptsReference

▸ **acceptsReference**(`argIndex`): `boolean`

Determines whether the function accepts Reference values for the specified argument.

**`function`**

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `argIndex` | `number` | Index of the argument. |

#### Returns

`boolean`

`true` if the function accepts Reference values for the specified argument; otherwise, `false`.

___

### <a id="description" name="description"></a> description

▸ **description**(): [`IFunctionDescription`](../interfaces/GC.Spread.CalcEngine.Functions.IFunctionDescription)

Returns the description of the function.

**`function`**

#### Returns

[`IFunctionDescription`](../interfaces/GC.Spread.CalcEngine.Functions.IFunctionDescription)

The description of the function.

___

### <a id="evaluate" name="evaluate"></a> evaluate

▸ **evaluate**(...`args`): `any`

Returns the result of the function applied to the arguments.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `...args` | `any` | Arguments for the function evaluation |

#### Returns

`any`

The result of the function applied to the arguments.

___

### <a id="findbranchargument" name="findbranchargument"></a> findBranchArgument

▸ **findBranchArgument**(`test`): `number`

Finds the branch argument.

**`example`**
```javascript
function EqualsFunction() {
    this.name = 'Equals';
    this.maxArgs = 3;
    this.minArgs = 3;
}
EqualsFunction.prototype = new GC.Spread.CalcEngine.Functions.Function();
EqualsFunction.prototype.evaluate = function(logicalTest, valueIfTrue, valueIfFalse) {
    return logicalTest ? valueIfTrue : valueIfFalse;
}
EqualsFunction.prototype.isBranch = function() {
    return true;
}
EqualsFunction.prototype.findTestArgument = function() {
    return 0;
}
EqualsFunction.prototype.findBranchArgument = function(logicalTestResult) {
    if (logicalTestResult === true) {
        return 1;
    }
    return 2;
}
var equalsFunction = new EqualsFunction();
var spread = GC.Spread.Sheets.findControl("ss") || GC.Spread.Sheets.findControl("sampleDiv");
spread.addCustomFunction(equalsFunction);
```

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| `test` | `any` | The test. |

#### Returns

`number`

Indicates the index of the argument that would be treated as the branch condition.

___

### <a id="findtestargument" name="findtestargument"></a> findTestArgument

▸ **findTestArgument**(): `number`

Finds the test argument when this function is branched.

**`example`**
```javascript
function EqualsFunction() {
    this.name = 'Equals';
    this.maxArgs = 3;
    this.minArgs = 3;
}
EqualsFunction.prototype = new GC.Spread.CalcEngine.Functions.Function();
EqualsFunction.prototype.evaluate = function(logicalTest, valueIfTrue, valueIfFalse) {
    return logicalTest ? valueIfTrue : valueIfFalse;
}
EqualsFunction.prototype.isBranch = function() {
    return true;
}
EqualsFunction.prototype.findTestArgument = function() {
    return 0;
}
EqualsFunction.prototype.findBranchArgument = function(logicalTestResult) {
    if (logicalTestResult === true) {
        return 1;
    }
    return 2;
}
var equalsFunction = new EqualsFunction();
var spread = GC.Spread.Sheets.findControl("ss") || GC.Spread.Sheets.findControl("sampleDiv");
spread.addCustomFunction(equalsFunction);
```

#### Returns

`number`

Indicates the index of the argument that would be treated as the test condition.

___

### <a id="isbranch" name="isbranch"></a> isBranch

▸ **isBranch**(): `boolean`

Gets a value that indicates whether this function is branched by arguments as conditional.

**`example`**
```javascript
function EqualsFunction() {
    this.name = 'Equals';
    this.maxArgs = 3;
    this.minArgs = 3;
}
EqualsFunction.prototype = new GC.Spread.CalcEngine.Functions.Function();
EqualsFunction.prototype.evaluate = function(logicalTest, valueIfTrue, valueIfFalse) {
    return logicalTest ? valueIfTrue : valueIfFalse;
}
EqualsFunction.prototype.isBranch = function() {
    return true;
}
EqualsFunction.prototype.findTestArgument = function() {
    return 0;
}
EqualsFunction.prototype.findBranchArgument = function(logicalTestResult) {
    if (logicalTestResult === true) {
        return 1;
    }
    return 2;
}
var equalsFunction = new EqualsFunction();
var spread = GC.Spread.Sheets.findControl("ss") || GC.Spread.Sheets.findControl("sampleDiv");
spread.addCustomFunction(equalsFunction);
```

#### Returns

`boolean`

`true` if this instance is branched; otherwise, `false`.

___

### <a id="iscontextsensitive" name="iscontextsensitive"></a> isContextSensitive

▸ **isContextSensitive**(): `boolean`

Determines whether the evaluation of the function is dependent on the context in which the evaluation occurs.

#### Returns

`boolean`

`true` if the evaluation of the function is dependent on the context; otherwise, `false`.

___

### <a id="isvolatile" name="isvolatile"></a> isVolatile

▸ **isVolatile**(): `boolean`

Determines whether the function is volatile while it is being evaluated.

#### Returns

`boolean`

`true` if the function is volatile; otherwise, `false`.