This is a javascript data mapping library. It allows you to create complex transferable logic and apply it to your data.
The idea was taken from this awesome repo. The initial goal of jsonmap is to create compatibility with JUST.net, but then it could be more adapted for JavaScript world.
You should provide some input raw data and transformer data that has jsonmap instructions that will be applied to input.
// your code for fetching json here, this is an example
const inputJson = fs.readFileSync(path.resolve(__dirname, `./input.json`), 'utf-8')
const transformerJson = fs.readFileSync(path.resolve(__dirname, `transformer.json`), 'utf-8')
const transformed = new JsonMap().transform(inputJson, transformerJson)Extracts value by provided path.
Input:
{
"menu": {
"popup": {
"menuitem": {
"open": "open-text",
"close": "close-text"
}
}
}
}Transformer:
{
"result": {
"Open": "#valueof($.menu.popup.menuitem.open)",
"Close": "#valueof($.menu.popup.menuitem.close)"
}
}Result:
{
"result": {
"Open": "open-text",
"Close": "close-text"
}
}Executes condition. Format: ifcondition(firstCompareArgument, secondCompareArgument, trueResult, falseResult)
Input:
{
"menu": {
"id": "github",
"repository": "jsonmap"
}
}Transformer:
{
"ifconditiontesttrue": "#ifcondition(#valueof($.menu.id),github,#valueof($.menu.repository),fail)",
"ifconditiontestfalse": "#ifcondition(#valueof($.menu.id),xml,#valueof($.menu.repository),fail)"
}Result:
{
"ifconditiontesttrue": "jsonmap",
"ifconditiontestfalse": "fail"
}Tranverses an array:
Input:
{
"numbers": [
1,
2,
3,
4
]
}Transformer:
{
"iteration": {
"#loop($.numbers)": {
"CurrentValue": "#currentvalue()",
"CurrentIndex": "#currentindex()"
}
}
}Result:
{
"iteration": [
{
"CurrentValue": 1,
"CurrentIndex": 0
},
{
"CurrentValue": 2,
"CurrentIndex": 1
},
{
"CurrentValue": 3,
"CurrentIndex": 2
},
{
"CurrentValue": 4,
"CurrentIndex": 3
}
]
}Input:
{
"string": "hello world",
"equalString": "hello world"
}Transformer:
{
"length": "#length($.string)",
"firstindexof": "#firstindexof($.string,world)",
"lastindexof": "#lastindexof($.string,o)",
"concat": "#concat($.string,abcd)",
"equals": "#stringequals($.string,$.equalString)",
"contains": "#stringcontains($.string,world)"
}Result:
{
"length": 11,
"firstindexof": 6,
"lastindexof": 7,
"concat": "hello worldabcd",
"equals": true,
"contains": true
}Input:
{
"numbers": [
2,
4,
8,
1.08
]
}Transformer:
{
"add": "#add($.numbers[0],$.numbers[1],2)",
"subtract": "#subtract($.numbers[2],$.numbers[1],$.numbers[0],1)",
"multiply": "#multiply($.numbers[0],$.numbers[1],$.numbers[2])",
"divide": "#divide($.numbers[2],$.numbers[1],$.numbers[0])",
"round": "#round($.numbers[3],1)",
"equals": "#mathequals($.numbers[0],2)",
"greater": "#mathgreaterthan(5,2)",
"less": "#mathlessthan(2,4)",
"greaterOrEqual": "#mathgreaterthanorequalto(4,4)",
"lessOrEqual": "#mathlessthanorequalto(4,4)"
} Result:
{
"add": 8,
"subtract": 1,
"multiply": 64,
"divide": 1,
"round": 1.1,
"equals": true,
"greater": true,
"less": true,
"greaterOrEqual": true,
"lessOrEqual": true
} Input:
{
"array": [
1,
2,
3
],
"stringArray": [
"hello",
" ",
"world"
]
} Transformer:
{
"length": "#length($.array)",
"concat": "#concatAll($.stringArray)",
"sum": "#sum(#valueof($.array))",
"average": "#average($.array)",
"min": "#min($.array)",
"max": "#max($.array)"
} Result:
{
"length": 3,
"concat": "hello world",
"sum": 6,
"average": 2,
"min": 1,
"max": 3
} Input:
{
"integer": 10,
"string": "",
"array": [
100
],
"boolean": false
}Transformer:
{
"isNumberTrue": "#isnumber(#valueof($.integer))",
"isNumberFalse": "#isnumber(#valueof($.string))",
"isStringTrue": "#isstring(#valueof($.string))",
"isStringFalse": "#isstring(#valueof($.integer))",
"isBooleanTrue": "#isboolean(#valueof($.boolean))",
"isArrayTrue": "#isarray(#valueof($.array))"
} Result:
{
"isNumberTrue": true,
"isNumberFalse": false,
"isStringTrue": true,
"isStringFalse": false,
"isBooleanTrue": true,
"isArrayTrue": true
} Type conversions
Input:
{
"booleans": {
"affirmative_string": "true",
"negative_string": "false",
"affirmative_int": 123,
"negative_int": 0
},
"strings": {
"integer": 123,
"decimal": 12.34,
"affirmative_boolean": true,
"negative_boolean": false
},
"integers": {
"string": "123",
"decimal": 1.23,
"affirmative_boolean": true,
"negative_boolean": false
},
"decimals": {
"integer": 123,
"string": "1.23"
}
}
24 Transformer:
{
"booleans": {
"affirmative_string": "#toboolean(#valueof($.booleans.affirmative_string))",
"negative_string": "#toboolean(#valueof($.booleans.negative_string))",
"affirmative_int": "#toboolean(#valueof($.booleans.affirmative_int))",
"negative_int": "#toboolean(#valueof($.booleans.negative_int))"
},
"strings": {
"integer": "#tostring(#valueof($.strings.integer))",
"decimal": "#tostring(#valueof($.strings.decimal))",
"affirmative_boolean": "#tostring(#valueof($.strings.affirmative_boolean))",
"negative_boolean": "#tostring(#valueof($.strings.negative_boolean))"
},
"integers": {
"string": "#tointeger(#valueof($.integers.string))",
"decimal": "#tointeger(#valueof($.integers.decimal))",
"affirmative_boolean": "#tointeger(#valueof($.integers.affirmative_boolean))",
"negative_boolean": "#tointeger(#valueof($.integers.negative_boolean))"
},
"decimals": {
"integer": "#todecimal(#valueof($.decimals.integer))",
"string": "#todecimal(#valueof($.decimals.string))"
}
} Result:
{
"booleans": {
"affirmative_string": true,
"negative_string": false,
"affirmative_int": true,
"negative_int": false
},
"strings": {
"integer": "123",
"decimal": "12.34",
"affirmative_boolean": "true",
"negative_boolean": "false"
},
"integers": {
"string": 123,
"decimal": 1,
"affirmative_boolean": 1,
"negative_boolean": 0
},
"decimals": {
"integer": 123.0,
"string": 1.23
}
}You could extend library functionality by declaring custom functions. Jsonmap's runtime will evaluate function's argument expressions and call this function.
NOTE: Raw value passed to custom function always parsed as string, in this case you should cast it to type you actualy need (for example, in #date(123) - 123 is a string
Example:
const jsonmap = new JsonMap()
jsonmap.declare('date', (unixtime) =>
// convert unix time to human readable date string
new Date(+unixtime * 1000).toDateString()
)Then use.
Input:
{
"unixTime": 863222400
}Transformer:
{
"humanReadableDate": "#date(#valueof($.unixTime))"
}Result:
{
"humanReadableDate": "Sat May 10 1997"
}