ts-expression-evaluator
v1.3.14
Published
Context-based expression parse and evaluator.
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ts-expression-evaluator
Context-based expression evaluator.
install
- npm
npm install ts-expression-evaluator
- yarn
yarn add ts-expression-evaluator
Quick start
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
Unary Operators
| Operation | Symbol | |-----------|:------:| | Negate | ! |
Binary Operators
| Operation | Symbol | |------------------|:----------------:| | Add, Concat | + | | Subtract | - | | Multiply | * | | Divide | / |
Logical Operators
| Operation | Symbol | |------------------|:----------------:| | Logical AND | && | | Logical OR | || |
Comparisons
| Comparison | Symbol | |----------------------------|:------:| | Equal | == | | Not equal | != | | Greater than | > | | Greater than or equal | >= | | Less than | < | | Less than or equal | <= |
Native Types
| Type | Examples |
|----------|:------------------------------:|
| Booleans | true
, false
|
| Strings | "Hello "user"", 'Hey there!' |
| Numerics | 6, -7.2, 5, -3.14159 |
| Arrays | ['hello', 'world!'] |
API
evaluate(exp: string, context: object): any
registerFunction(name: string, func: Function): void
registerFunctions(funcs: {[key: string]: Function}): void
License
MIT