ts-expression-evaluator

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[![build status][travis-image]][travis-url]
[![Coverage Status][cov-image]][cov-status]

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[cov-status]: https://coveralls.io/github/william-yz/ts-expression-evaluator?branch=master

Context-based expression evaluator.

install

- npm
npm install ts-expression-evaluator
- yarn
yarn add ts-expression-evaluator

Quick start

javascript
import evaluate, { registerFunction } from 'ts-expression-evaluator'
const context = {
  id: 10,
  name: 'FED',
  count: 10,
  staffs: [{
    id: 1,
    name: 'Tina'
  }, {
    id: 2,
    name: 'James'
  }],
}
// math
evaluate('1+2') // 3
// eval from context
evaluate('name', context) // 'FED'
evaluate('staffs[0].name', context) // 'Tina'
evaluate('count + 10', context) // 20
// ===
evaluate('count === 11', context) // false
// register custom function
registerFunction('IF', (condition, ifTrue, ifFalse) => {
  return condition ? ifTrue : ifFalse;
})
evaluate('IF(name === 'FED', 'It\'s FED.', 'It\'s not FED.')') // It's FED.

// array filter evaluate('staffs[this.id === 1]', context) // [{id: 1, name: 'Tina'}]`

`Details`


$3
| Operation | Symbol |
|-----------|:------:|
| Negate    |    !   |
$3
| Operation        |      Symbol      |
|------------------|:----------------:|
| Add, Concat      |         +        |
| Subtract         |         -        |
| Multiply         |         *        |
| Divide           |         /        |
$3
| Operation        |      Symbol      |
|------------------|:----------------:|
| Logical AND      |        &&        |
| Logical OR       |   ||   |
$3
| Comparison                 | Symbol |
|----------------------------|:------:|
| Equal                      |   ==   |
| Not equal                  |   !=   |
| Greater than               |    >   |
| Greater than or equal      |   >=   |
| Less than                  |    <   |
| Less than or equal         |   <=   |
$3

| Type | Examples | |----------|:------------------------------:| | Booleans |true, false` |
| Strings | "Hello \"user\"", 'Hey there!' |
| Numerics | 6, -7.2, 5, -3.14159 |
| Arrays | ['hello', 'world!'] |

API

$3

License

MIT

ts-expression-evaluator

[![NPM version][npm-image]][npm-url]
[![build status][travis-image]][travis-url]
[![Coverage Status][cov-image]][cov-status]

Context-based expression evaluator.

Quick start

javascript
import evaluate, { registerFunction } from 'ts-expression-evaluator'
const context = {
id: 10,
name: 'FED',
count: 10,
staffs: [{
id: 1,
name: 'Tina'
}, {
id: 2,
name: 'James'
}],
}

// math
evaluate('1+2') // 3

// eval from context
evaluate('name', context) // 'FED'
evaluate('staffs[0].name', context) // 'Tina'
evaluate('count + 10', context) // 20

// ===
evaluate('count === 11', context) // false

// register custom function
registerFunction('IF', (condition, ifTrue, ifFalse) => {
return condition ? ifTrue : ifFalse;
})

evaluate('IF(name === 'FED', 'It\'s FED.', 'It\'s not FED.')') // It's FED.

// array filter
evaluate('staffs[this.id === 1]', context) // [{id: 1, name: 'Tina'}]

Details

$3

| Operation | Symbol |
|-----------|:------:|
| Negate | ! |

$3

| Operation | Symbol |
|------------------|:----------------:|
| Add, Concat | + |
| Subtract | - |
| Multiply | * |
| Divide | / |

$3

| Operation | Symbol |
|------------------|:----------------:|
| Logical AND | && |
| Logical OR | || |

$3

| Comparison | Symbol |
|----------------------------|:------:|
| Equal | == |
| Not equal | != |
| Greater than | > |
| Greater than or equal | >= |
| Less than | < |
| Less than or equal | <= |

$3

| Type     |            Examples            |
|----------|:------------------------------:|
| Booleans |