Return a constructor for creating arrays having a fixed-width composite data type.
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> Return a constructor for creating arrays having a fixed-width composite data type.
``bash`
npm install @stdlib/array-struct-factory
`javascript`
var structFactory = require( '@stdlib/array-struct-factory' );
#### structFactory( arg )
Returns a constructor for creating arrays having a fixed-width composite data type.
`javascript`
var schema = [
{
'name': 'beep',
'type': 'float64'
},
{
'name': 'boop',
'type': 'int32'
}
];
var StructArray = structFactory( schema );
// returns
The function supports the following parameters:
- arg: [struct][@stdlib/dstructs/struct] constructor or a [struct][@stdlib/dstructs/struct] schema.
*
#### StructArray()
TODO: add documentation of constructor
*
#### StructArray.BYTES_PER_ELEMENT
Number of bytes per view element.
`javascript
var schema = [
{
'name': 'foo',
'type': 'bool'
}
];
var StructArray = structFactory( schema );
var nbytes = StructArray.BYTES_PER_ELEMENT;
// returns 1
`
#### StructArray.name
Array constructor name.
`javascript
var schema = [
{
'name': 'foo',
'type': 'bool'
}
];
var StructArray = structFactory( schema );
var str = StructArray.name;
// returns 'StructArray'
`
#### StructArray.prototype.buffer
Read-only property which returns the [ArrayBuffer][@stdlib/array/buffer] referenced by the array.
`javascript
var schema = [
{
'name': 'foo',
'type': 'bool'
}
];
var StructArray = structFactory( schema );
var arr = new StructArray( 5 );
var buf = arr.buffer;
// returns
`
#### StructArray.prototype.byteLength
Read-only property which returns the length (in bytes) of the array.
`javascript
var schema = [
{
'name': 'foo',
'type': 'int32'
}
];
var StructArray = structFactory( schema );
var arr = new StructArray( 5 );
var byteLength = arr.byteLength;
// returns 20
`
#### StructArray.prototype.byteOffset
Read-only property which returns the offset (in bytes) of the array from the start of its [ArrayBuffer][@stdlib/array/buffer].
`javascript
var schema = [
{
'name': 'foo',
'type': 'bool'
}
];
var StructArray = structFactory( schema );
var arr = new StructArray( 5 );
var byteOffset = arr.byteOffset;
// returns 0
`
#### StructArray.prototype.BYTES_PER_ELEMENT
Number of bytes per view element.
`javascript
var schema = [
{
'name': 'foo',
'type': 'bool'
}
];
var StructArray = structFactory( schema );
var arr = new StructArray( 5 );
var nbytes = arr.BYTES_PER_ELEMENT;
// returns 1
`
#### StructArray.prototype.length
Read-only property which returns the number of view elements.
`javascript
var schema = [
{
'name': 'foo',
'type': 'bool'
}
];
var StructArray = structFactory( schema );
var arr = new StructArray( 5 );
var len = arr.length;
// returns 5
`
*
TODO: document methods
*
- While returned constructors _strive_ to maintain (but do not guarantee) consistency with [typed arrays][@stdlib/array/typed], significant deviations from ECMAScript-defined [typed array][@stdlib/array/typed] behavior are as follows:
- Constructors do not require the new operator.X[i]
- Accessing array elements using bracket syntax (e.g., ) is not supported. Instead, one must use the .get() method.
- Accessed array elements are a view on underlying memory. Thus, mutation of accessed elements mutates the underlying buffer.
- Struct arrays share several similarities with generic arrays containing objects (e.g., nested property access); however, the principal difference is that struct arrays are strongly typed and backed by fixed memory. Struct arrays are particularly well-suited for zero-copy transfer of data stored in composite data types when interoperating between JavaScript and C.
`javascript
var factory = require( '@stdlib/array-struct-factory' );
// Define a schema for a composite data type for storing a student's test scores:
var schema = [
{
'name': 'test_number',
'type': 'int16'
},
{
'name': 'pass',
'type': 'bool'
},
{
'name': 'correct',
'type': 'int32'
},
{
'name': 'incorrect',
'type': 'int32'
},
{
'name': 'percentage',
'type': 'float32'
}
];
// Create an array constructor for creating composite data type arrays:
var TestScoreArray = factory( schema );
console.log( 'Layout: %s', TestScoreArray.struct.layout );
// Create a new array for storing test scores:
var student1 = new TestScoreArray( 10 );
console.log( 'Byte length: %d', student1.byteLength );
`
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
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---
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