Class ArrayConstraint<T>

Note: the preferred way to create an array constraint is with cjs([...]) or cjs.array(options).

Emulates a standard array, but with constraints: its methods (push, pop, slice, ...) keep track of dependencies, so that a constraint that reads an item is only updated when that item (or, for methods like forEach, the length) changes.

x[1] = y[2] + z[3]  ===  x.item(1, y.item(2) + z.item(3))

Example

var arr = cjs([1, 2, 3]);
    var sum = cjs(function() {
        return arr.toArray().reduce(function(a, b) { return a + b; }, 0);
    });
    sum.get(); // 6
    arr.push(4);
    sum.get(); // 10

Type Parameters

T = any

Index

Constructors

constructor

Properties

BREAK

Constructors

constructor

new ArrayConstraint<T = any>(
options?: ArrayConstraintOptions<T>,
): ArrayConstraint<T>
Type Parameters
- T = any
Parameters
- Optionaloptions: ArrayConstraintOptions<T>
Returns ArrayConstraint<T>
- Defined in array-constraint.ts:50

Properties

`Static` `Readonly`BREAK

BREAK: object = BREAK

Return this from a forEach callback to stop iterating.

Methods

concat

concat(...values: unknown[]): unknown[]
A new (plain) array of these items followed by values. Array (and array constraint) arguments are spread into the result.
Parameters
- ...values: unknown[]
Returns unknown[]
Example
```
var arr1 = cjs(['a','b','c']),
        arr2 = cjs(['x']);
    arr1.concat(arr2); // ['a','b','c','x']
```
- Defined in array-constraint.ts:375

destroy

destroy(silent?: boolean): void
Clears this array and cleans up its constraints.
Parameters
- Optionalsilent: boolean
  If true, don't invalidate the constraints that depended on it
Returns void
- Defined in array-constraint.ts:150

every

every(
filter: (this: any, value: T, index: number) => unknown,
thisArg?: unknown,
): boolean
Whether filter returns a truthy value for every item.
Parameters
- filter: (this: any, value: T, index: number) => unknown
- OptionalthisArg: unknown
Returns boolean
Example
```
var arr = cjs([2,4,6]);
    arr.every(function(x) { return x%2===0; }); // true
```
- Defined in array-constraint.ts:299

filter

filter(
filter: (value: T, index: number, array: T[]) => unknown,
thisArg?: unknown,
): T[]
A (plain) array of the items that pass filter.
Parameters
- filter: (value: T, index: number, array: T[]) => unknown
- OptionalthisArg: unknown
Returns T[]
- Defined in array-constraint.ts:409

forEach

forEach(
callback: (this: any, value: T, index: number) => unknown,
thisArg?: unknown,
): this
Calls callback once per item. Return cjs.ArrayConstraint.BREAK from it to stop.
Parameters
- callback: (this: any, value: T, index: number) => unknown
- thisArg: unknown = globalThis
  The this for callback (default: the global object)
Returns this
Example
```
var arr = cjs(['a','b','c']);
    arr.forEach(function(val, i) {
        console.log(val);
        if(i === 1) {
            return cjs.ArrayConstraint.BREAK;
        }
    }); // 'a' ... 'b'
```
- Defined in array-constraint.ts:79

indexOf

indexOf(item: T, equalityCheck?: EqualityCheck<T>): number
The index of the first item equal to item, or -1.
Parameters
- item: T
- OptionalequalityCheck: EqualityCheck<T>
  How to compare items (default: this array's equality check)
Returns number
Example
```
var arr = cjs(['a','b','a']);
    arr.indexOf('a'); // 0
```
- Defined in array-constraint.ts:262

indexWhere

indexWhere(
filter: (this: any, value: T, index: number) => unknown,
thisArg?: unknown,
): number
The index of the first item for which filter returns a truthy value, or -1.
Parameters
- filter: (this: any, value: T, index: number) => unknown
- thisArg: unknown = ...
  The this for filter (default: this array constraint)
Returns number
Example
```
var arr = cjs(['a','b','b']);
    arr.indexWhere(function(val, i) {
        return val === 'b';
    }); // 1
```
- Defined in array-constraint.ts:227

item

item(): T[]
With no arguments: a plain array of the items (see toArray). With index: the item at index. With index and value: sets the item at index and returns value.

Returns T[]
Example
```
var arr = cjs(['a','b']);
    arr.item();        // ['a','b']
    arr.item(0);       // 'a'
    arr.item(0, 'x');
    arr.toArray();     // ['x','b']
```
- Defined in array-constraint.ts:129
item(index: number): T | undefined
With no arguments: a plain array of the items (see toArray). With index: the item at index. With index and value: sets the item at index and returns value.
Parameters
- index: number
Returns T | undefined
Example
```
var arr = cjs(['a','b']);
    arr.item();        // ['a','b']
    arr.item(0);       // 'a'
    arr.item(0, 'x');
    arr.toArray();     // ['x','b']
```
- Defined in array-constraint.ts:130
item(index: number, value: T): T
With no arguments: a plain array of the items (see toArray). With index: the item at index. With index and value: sets the item at index and returns value.
Parameters
- index: number
- value: T
Returns T
Example
```
var arr = cjs(['a','b']);
    arr.item();        // ['a','b']
    arr.item(0);       // 'a'
    arr.item(0, 'x');
    arr.toArray();     // ['x','b']
```
- Defined in array-constraint.ts:131

itemConstraint

itemConstraint(index: number | Constraint<number>): Constraint<T | undefined>
A constraint whose value is the item at index (which can itself be a constraint).
Parameters
- index: number | Constraint<number>
Returns Constraint<T | undefined>
Example
```
var arr = cjs(['a','b','c']);
    var first_item = arr.itemConstraint(0);
    first_item.get(); // 'a'
    arr.item(0,'x');
    first_item.get(); // 'x'
```
- Defined in array-constraint.ts:404

join

join(separator?: string): string
The items joined into a string, separated by separator (default: ",").
Parameters
- Optionalseparator: string
Returns string
- Defined in array-constraint.ts:414

lastIndexOf

lastIndexOf(item: T, equalityCheck?: EqualityCheck<T>): number
The index of the last item equal to item, or -1.
Parameters
- item: T
- OptionalequalityCheck: EqualityCheck<T>
  How to compare items (default: this array's equality check)
Returns number
Example
```
var arr = cjs(['a','b','a']);
    arr.lastIndexOf('a'); // 2
```
- Defined in array-constraint.ts:276

lastIndexWhere

lastIndexWhere(
filter: (this: any, value: T, index: number) => unknown,
thisArg?: unknown,
): number
The index of the last item for which filter returns a truthy value, or -1.
Parameters
- filter: (this: any, value: T, index: number) => unknown
- thisArg: unknown = ...
  The this for filter (default: this array constraint)
Returns number
Example
```
var arr = cjs(['a','b','a']);
    arr.lastIndexWhere(function(val, i) {
        return val === 'a';
    }); // 2
```
- Defined in array-constraint.ts:246

length

length(): number
The number of items.

Returns number
Example
```
var arr = cjs(['a','b']);
    arr.length(); // 2
```
- Defined in array-constraint.ts:168

map

map<R>(
callback: (this: any, value: T, index: number) => R,
thisArg?: unknown,
): R[]
A new (plain) array with the results of calling callback on every item.
Type Parameters
- R
Parameters
- callback: (this: any, value: T, index: number) => R
- thisArg: unknown = globalThis
Returns R[]
Example
```
var arr = cjs([1,2,3]);
    arr.map(function(x) { return x+1; }); // [2,3,4]
```
- Defined in array-constraint.ts:94

pop

pop(): T | undefined
Removes the last item and returns it (or undefined if the array is empty).

Returns T | undefined
Example
```
var arr = cjs(['a','b']);
    arr.pop(); // 'b'
    arr.toArray(); // ['a']
```
- Defined in array-constraint.ts:197

push

push(...values: T[]): number
Appends items to the end and returns the new length.
Parameters
- ...values: T[]
Returns number
Example
```
var arr = cjs(['a','b']);
    arr.push('c','d'); // 4
    arr.toArray(); // ['a','b','c','d']
```
- Defined in array-constraint.ts:180

reverse

reverse(): T[]
A reversed (plain) copy of the items. This array constraint is not modified.

Returns T[]
- Defined in array-constraint.ts:424

setEqualityCheck

setEqualityCheck(equalityCheck: EqualityCheck<T>): this
Change how items are compared (for indexOf and friends).
Parameters
- equalityCheck: EqualityCheck<T>
Returns this
- Defined in array-constraint.ts:60

setValue

setValue(values: readonly T[]): this
Replaces every item.
Parameters
- values: readonly T[]
Returns this
Example
```
var arr = cjs([1,2,3]);
    arr.setValue(['a','b','c']);
    arr.toArray(); //['a','b','c']
```
- Defined in array-constraint.ts:110

shift

shift(): T | undefined
Removes the first item and returns it.

Returns T | undefined
Example
```
var arr = cjs(['a','b','c']);
    arr.shift(); // 'a'
    arr.toArray(); //['b','c']
```
- Defined in array-constraint.ts:349

slice

slice(begin?: number, end?: number): T[]
A (plain) array of the items from begin up to (but not including) end. Like Array.prototype.slice, negative indices count back from the end.
Parameters
- Optionalbegin: number
- Optionalend: number
Returns T[]
Example
```
var arr = cjs(['a','b','c']);
    arr.slice(1); // ['b','c']
```
- Defined in array-constraint.ts:388

some

some(
filter: (this: any, value: T, index: number) => unknown,
thisArg?: unknown,
): boolean
Whether filter returns a truthy value for any item.
Parameters
- filter: (this: any, value: T, index: number) => unknown
- OptionalthisArg: unknown
Returns boolean
Example
```
var arr = cjs([1,3,5]);
    arr.some(function(x) { return x%2===0; }); // false
```
- Defined in array-constraint.ts:288

sort

sort(compareFunction?: (a: T, b: T) => number): T[]
A sorted (plain) copy of the items. This array constraint is not modified.
Parameters
- OptionalcompareFunction: (a: T, b: T) => number
Returns T[]
- Defined in array-constraint.ts:419

splice

splice(index: number, howMany?: number, ...items: T[]): T[]
Removes howMany items starting at index, inserts items in their place, and returns the removed items. If index is past the end, items are appended.
Parameters
- index: number
- OptionalhowMany: number
  The number of items to remove (default: 0)
- ...items: T[]
Returns T[]
Example
```
var arr = cjs(['a','b','c']);
    arr.splice(0, 2, 'x', 'y'); // ['a','b']
    arr.toArray(); // ['x','y','c']
```
- Defined in array-constraint.ts:322

toArray

toArray(): T[]
A plain array of the items.

Returns T[]
Example
```
var arr = cjs(['a','b']);
    arr.toArray(); // ['a', 'b']
```
- Defined in array-constraint.ts:212

toString

toString(): string
The items as a string, like Array.prototype.toString.

Returns string
- Defined in array-constraint.ts:429

unshift

unshift(...items: T[]): number
Adds items to the beginning and returns the new length.
Parameters
- ...items: T[]
Returns number
Example
```
var arr = cjs(['a','b','c']);
    arr.unshift('x','y'); // 5
    arr.toArray(); //['x','y','a','b','c']
```
- Defined in array-constraint.ts:361

Class ArrayConstraint<T>

Example

Type Parameters

Index

Constructors

Properties

Methods

Constructors

constructor

Type Parameters

Parameters

Returns ArrayConstraint<T>

Properties

Static ReadonlyBREAK

Methods

concat

Parameters

Returns unknown[]

Example

destroy

Parameters

Returns void

every

Parameters

Returns boolean

Example

filter

Parameters

Returns T[]

forEach

Parameters

Returns this

Example

indexOf

Parameters

Returns number

Example

indexWhere

Parameters

Returns number

Example

item

Returns T[]

Example

Parameters

Returns T | undefined

Example

Parameters

Returns T

Example

itemConstraint

Parameters

Returns Constraint<T | undefined>

Example

join

Parameters

Returns string

lastIndexOf

Parameters

Returns number

Example

lastIndexWhere

Parameters

Returns number

Example

length

Returns number

Example

map

Type Parameters

Parameters

Returns R[]

Example

pop

Returns T | undefined

Example

push

Parameters

Returns number

Example

`Static` `Readonly`BREAK