# invoke-if
> A powerful control-flow invoker based on the structure of ES6 Maps
Latest version **2.1.1** (published 2017-11-17) · MIT license · 0 weekly downloads
## Install
```sh
npm install invoke-if
pnpm add invoke-if
yarn add invoke-if
bun add invoke-if
```
## Health
**Score 20/100 (F)** — status: abandoned.
Positive: esm support; no vulnerabilities.
Warnings: low downloads; no types.
Negative: abandoned; low maintenance score.
## Facts
| | |
|---|---|
| Version | 2.1.1 |
| Published | 2017-11-17 |
| First published | 2017-05-29 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | ESM + CommonJS |
| Dependencies | 0 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 0 |
| Author | Braden R. Napier |
| Maintainers | bradynapier |
| Keywords | invoke, utility, function, switch, if, flow, control |
## Links
- npm: https://www.npmjs.com/package/invoke-if
- Repository: https://github.com/Dash-OS/invoke-if
- Homepage: https://github.com/Dash-OS/invoke-if#readme
- Issues: https://github.com/Dash-OS/invoke-if/issues
- npm.io page: https://npm.io/package/invoke-if
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## Recent versions
- 2.1.1 (latest) — 2017-11-17
- 2.1.0 — 2017-11-17
- 2.0.0 — 2017-11-17
- 1.2.1 — 2017-05-30
- 1.2.0 — 2017-05-29
- 1.1.0 — 2017-05-29
- 1.0.1 — 2017-05-29
## README
# invoke-if
A dependency-free micro-package providing composable control-flow that works the
way we always wished `switch` would work. It evaluates groups of tests and
provides a pattern for if, if/and, if/else, if/then.
Each test that passes invokes that tests function or array of functions.
Optionally aggregates the results of the passing invokes to the caller.
## Installation
```
yarn add invoke-if
```
**or**
```
npm install --save invoke-if
```
## Flow Coverage
Proudly built with 100% Flow Coverage. Includes flow definitions so if you are
using flow, it will type-check for you.
## Breaking Update
Version 2.0 implements a change of the API for `invoke-if`. Previous versions
are not likely to work. These changes were done during perf tests when we
realized 90% speed improvements by slightly adjusting the data structure that
invoke-if operates upon.
## Examples
```js
/* @flow */
import { log } from '../utils/log';
import invokeIf, { invokeMap } from '../src/main';
log('Begin InvokeIf Basic Tests');
// Note that `log()` returns the result of performance.now()
const INVOKE_TESTS = [
[
[true, () => log('one')],
[true, () => log('two')],
[false, () => log('three')],
[false, () => log('four')],
],
new Map([
[() => true, () => log('five')],
[() => 'true', () => log('six')],
[() => 'seven', (arg: string) => log(arg)],
]),
];
function one() {
log('Running Example One (invokeReduce / default)');
return invokeIf(...INVOKE_TESTS);
}
function two() {
log('Running Example Two (invokeMap)');
return invokeMap(...INVOKE_TESTS);
}
log('Example One Result: \n', one());
log('Example Two Result: \n', two());
/*
+1.5743 695406726.602197 Begin InvokeIf Basic Tests
+1.3778 695406727.980045 Running Example One (invokeReduce / default)
+0.3265 695406728.306522 one
+0.0703 695406728.376835 two
+0.0808 695406728.457588 five
+0.0625 695406728.520046 six
+0.0531 695406728.573129 seven
+0.0336 695406728.606769 Example One Result:
[
695406728.306522,
695406728.376835,
695406728.457588,
695406728.520046,
695406728.573129
]
+1.2038 695406729.810552 Running Example Two (invokeMap)
+0.0957 695406729.906205 one
+0.0450 695406729.951161 two
+0.0308 695406729.981922 five
+0.0267 695406730.008638 six
+0.0256 695406730.034196 seven
+0.0245 695406730.058679 Example Two Result:
[
[ 695406729.906205, 695406729.951161 ],
[ 695406729.981922, 695406730.008638, 695406730.034196 ]
]
*/
```
> There are many examples / tests available in the
> [examples directory](https://github.com/Dash-OS/invoke-if/tree/master/examples)
---
## Type Signatures
```js
export type $NonFunction = boolean | string | number | { [key: string]: * };
export type InvokeCheck<+A> = (() => A) | A;
export type InvokeFn = (arg: A) => mixed;
export type Invoker =
| Array | $NonFunction>
| (InvokeFn | $NonFunction);
export type ElseInvoker =
| Array | $NonFunction>
| (InvokeFn | $NonFunction);
export type InvokeTest =
| [InvokeCheck, Invoker]
| [InvokeCheck, Invoker, ElseInvoker];
export type FactoryFn = () => void | false | null | InvokeTesters;
export type InvokeTesters =
| Array>
| Map, Invoker>
| FactoryFn;
```
---
## Module Exports
### invokeReduce (Function) (default, named)
The default export, reduces the results of the tests into a simple array of
results.
```js
declare function invokeReduce(...tests: Array>): Array;
```
### invokeMap (Function)
Instead of reducing and merging the responses together, `invokeMap` simply runs
the tests and maps the responses directly to the caller. The result is an array
of results which are a closer match to the original array.
```js
declare function invokeMap(...tests: Array>): Array;
```
### invokeAny (Function)
A shortcut for handling the situation when you want to evaluate every entry
regardless of if a `falsey` value is found within the chain.
It is an alias for doing something like:
```js
invokeIf(
[[true, () => console.log(1)]],
[[true, () => console.log(2)]],
[[false, () => console.log(3)]],
[[true, () => console.log(4)]],
);
// Same as
invokeAny(
[true, () => console.log(1)],
[true, () => console.log(2)],
[false, () => console.log(3)],
[true, () => console.log(4)],
);
```
```js
declare function invokeAny(...tests: Array>): Array;
```
---
## Control Flow
`invoke-if` makes composing various situations much simpler then nesting if/else
statements of using switches in many cases. Below is a description of how the
arguments will be evaluated.
### if/if...
`invoke-if` evaluates entry within an argument until the it encounters a check
that results in a `falsey` response. In the nested example below, we would
invoke entries 1 and 2 while 3 and 4 would not occur since evaluating 3
resulting in a `falsey` result.
```js
invokeIf([
['true', () => console.log(1)],
[() => true, () => console.log(2)],
[false, () => console.log(3)],
[true, () => console.log(4)],
]);
```
### if/then
`invoke-if` evaluates each argument independently of the others. Each separate
argument sent to one of `invoke-if`'s functions can be thought of as `then`
arguments.
In the example below, we would invoke arguments 1, 2, 5, and 6.
```js
invokeIf(
[
['true', () => console.log(1)],
[() => true, () => console.log(2)],
[false, () => console.log(3)],
[true, () => console.log(4)],
],
[
['true', () => console.log(5)],
[() => true, () => console.log(6)],
[false, () => console.log(7)],
[true, () => console.log(8)],
],
);
```
### if/else
When encountering a failed argument, `invoke-if` will check if there is a third
element to the entry (not compatible with `Map`). If there is, it will invoke
the third element and add it to the results before breaking evaluation of the
given argument.
In the example above it will print `1` then `2` then `'done'`
```js
const done = () => console.log('done');
invokeIf([
['true', () => console.log(1), done],
[() => true, () => console.log(2), done],
[false, () => console.log(3), done],
[true, () => console.log(4), done],
]);
```
### Customized Flow
When encountering a function rather than an Array or Map, it will assume that
the function is a factory. It will first call the function and will evaluate the
result if it can.
The example below will toggle which case is executed each time any of the
current elements tests encounters a `falsey` response.
```js
let i = 0;
const done = () => {
i += 1;
console.log('done');
};
function doinvoke() {
return invokeIf(
() =>
i % 2 === 0 && [
['true', () => console.log(1), done],
[() => true, () => console.log(2), done],
[false, () => console.log(3), done],
[true, () => console.log(4), done],
],
() =>
i % 2 !== 0 && [
['true', () => console.log(5), done],
[() => true, () => console.log(6), done],
[false, () => console.log(7), done],
[true, () => console.log(8), done],
],
);
}
```
---
_Source: https://npm.io/package/invoke-if · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._