nullable-json-pn
v1.0.1
Published
JSON templates in prefix notation
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nullable-json-pn
Fork of json-pn
with support of nullable fields for more flaky operations
Simple JSON template language in Polish notation
Motivation
Sometimes you would like to encode JSON template by JSON object.
Features
- Template encoded by JSON object in Polish notation
- Support of mathematical and logical operations
- Support of custom operations
- Conditional operator
- Map operator
Usage
Include
import { createCompiler } from 'json-pn'
Create compiler
const compiler = createCompiler()
Create template function
const hello = compiler({ '@add': ['Hello', { '@': 'value' }] })
Use template function
console.log(hello({ value: ' word' })) //Hello word
Custom operators
You can manually set list of supported operators.
import { createCompiler, defaultOperationsMap } from 'json-pn'
const compiler = createCompiler(defaultOperationsMap)
You can register your own operator during compiler creation
import {createCompiler, defaultOperationsMap} from 'json-pn'
const double = compiler => value => {
const subtemplate = compiler(value)
return props => subtemplate(props) * 2
}
const compiler = createCompiler({
...defaultOperationsMap,
'@double': double
})
const four = compiler({'@double': 2)
console.log(four())//4
Operators
Operators types
Unar operators
Unar operator use value as single parameter
// ! true
{'@not': true}
N-ar operatprs
N-ar operators always expects array fixed length. According to operands count can be defined binar, triar, and other operators
// 2 + 4
{'@add': [ 2, 4 ]}
//if (true) {return 'foo'} else {return 'baz'}
{'@if': [true, 'foo', 'baz']}
Operators grpups
Template parameters
@ operator
Unar operator expects string or string[] in operand.
Special
@escape operator
Unar operator. Just copy operand value without any transformations.
Mathematical
@add
Binar operator.
@rem
Binar operator.
@mul
Binar operator.
@div
Binar operator.
Logical
@not
Unar operator.
@and
Binar operator.
@or
Binar operator.
Comparation
@lt
Binar operator.
@le
Binar operator.
@eq
Binar operator.
@ge
Binar operator.
@gt
Binar operator.
Array operators
@map operator
Tetrar operator. Allows to use template for each array item.
| Operand number | Operand value | | -------------- | -------------------------------------------- | | 0 | Target array | | 1 | Template | | 2 | Array item name it template parameters | | 3 | Array item index name in template parameters |
//[1,2,3].map((x,i) => 2 * x + i)
{
"@map" : [
[1, 2, 3], {
"@add": [
"@mul" : [ 2, {"@":"x"}],
{"@":"i"}
]
},
"x","i"
]
}