Enhanced-switch NPM

EnhancedSwitch

An enhanced switch, similar to Java.

This library targets Node.js 16, 18 and 20, but can also work in the browser.

Installation

npm i enhanced-switch

Usage

TypeScript

import EnhancedSwitch from "enhanced-switch";

const value = 2;

new EnhancedSwitch(value)
    .case(1, () => console.log("one"))
    .case(2, () => console.log("two"))
    .default(() => console.log("default"));

const result = new EnhancedSwitch<number, string>(value)
    .case(1, () => "one")
    .case(2, () => "two")
    .default(() => "default").value;

JavaScript

import EnhancedSwitch from "enhanced-switch";

const value = 2;

new EnhancedSwitch(value)
    .case(1, () => console.log("one"))
    .case(2, () => console.log("two"))
    .default(() => console.log("default"));

const result = new EnhancedSwitch(value)
    .case(1, () => "one")
    .case(2, () => "two")
    .default(() => "default").value;

Documentation

Class EnhancedSwitch<T, U>

Class `EnhancedSwitch<T, U>`

The EnhancedSwitch evaluates an expression, matching the expression's value against a series of case clauses, and executes the statements after the first case clause with a matching value. The default clause of an EnhancedSwitch will be jumped to if no case matches the expression's value.

Template parameter	Description
`T`	Switch expression type
`U`	Switch return type

`new EnhancedSwitch(expression: T)`

Create a new EnhancedSwitch

Parameter	Type	Description
`expression`	`T`	An expression whose result is matched against each `case` clause.

`enhancedSwitch.allowFallthrough`

Whether to allow fallthrough. If true, the switch will continue to execute case clauses after the first match until a break is encountered. Defaults to false.

Type: boolean. Read-only.

`enhancedSwitch.break()`

Prevent further execution of any subsequent case or default clauses.

Returns: this (EnhancedSwitch<T, U>)

`enhancedSwitch.case(valueN: T | T[], code: U)`

A case clause used to match against expression. If the expression matches the specified valueN (which can be any expression), this case clause is executed.

Parameter	Type	Description
`valueN`	`T`	The `case` clause is executed if the expression matches this value, or at least one value if this is an array.
`code`	`U`	The value to return if the case matches.

Returns: this (EnhancedSwitch<T, U>)

`enhancedSwitch.case(valueN: T | T[], code: (s: EnhancedSwitch<T, U>) => U | void)`

A case clause used to match against expression. If the expression matches the specified valueN (which can be any expression), this case clause is executed.

Parameter	Type	Description
`valueN`	`T`	The `case` clause is executed if the expression matches this value, or at least one value if this is an array.
`code`	`(s: EnhancedSwitch<T, U>) => U \\| void`	The function to run if the case matches.

Returns: this (EnhancedSwitch<T, U>)

`enhancedSwitch.default(code: U)`

A default clause; if provided, this clause is executed if the value of expression does not match any of the case clauses. An EnhancedSwitch can only have one default clause.

Parameter	Type	Description
`code`	`U`	The value to return if no case matches.

Returns: this (EnhancedSwitch<T, U>)

`enhancedSwitch.default(code: (s: EnhancedSwitch<T, U>) => U | void)`

A default clause; if provided, this clause is executed if the value of expression does not match any of the case clauses. An EnhancedSwitch can only have one default clause.

Parameter	Type	Description
`code`	`(s: EnhancedSwitch<T, U>) => U \\| void`	The function to run if no case matches.

Returns: this (EnhancedSwitch<T, U>)

`enhancedSwitch.default(code: U, returnvalueN: true)`

A default clause; if provided, this clause is executed if the value of expression does not match any of the case clauses. An EnhancedSwitch can only have one default clause.

Parameter	Type	Description
`code`	`U`	The value to return if no case matches.
`returnvalueN`	`true`	If true, the provided value is returned instead of the switch instance.

Returns: U

`enhancedSwitch.default(code: (s: EnhancedSwitch<T, U>) => U | void, returnvalueN: true)`

A default clause; if provided, this clause is executed if the value of expression does not match any of the case clauses. An EnhancedSwitch can only have one default clause.

Parameter	Type	Description
`code`	`(s: EnhancedSwitch<T, U>) => U \\| void`	The function to run if no case matches.
`returnvalueN`	`true`	If true, the provided value is returned instead of the switch instance.

Returns: U

`enhancedSwitch.expression`

An expression whose result is matched against each case clause.

Type: T. Read-only.

`enhancedSwitch.hasConcluded`

Whether the switch statement has concluded (no further case or default will be executed). A switch can be concluded by calling enhancedSwitch.break() or constructing with allowFallthrough set to false.

Type: boolean. Read-only.