jsonexpression

JSON is great in representing static data however there are many cases that we need standard way to represent dynamic data in JSON itself

Reserved names

name in JSON that use for operators

name	Operators or special variable
and
or
equal
greater
less
lessOrEqual
greaterOrEqual
not
in
notin
name
value

Simple expression

operator	JSON expression	JSON data to evaluate	Result in native value e.g., true or false, 1,2, [1,2]	note
Reference a field value	{“name”:”data”}	{“data”:100}	100
A native value	100 1.2 “hello world” true false [1,2,3,4] [1,2,”text”,null] null		100 1.2 “hello world” true false [1,2,3,4] [1,2,”text”,null] null	string, number, boolean, null, array of values without type conversion no date value
equal	{“$data”:100}	{“data”:100}	true	data === 100 reference a property in JSON object using ${name}
equal null	{“$data”:null}	{“data”:null} {“abc”:123}	true true	data === null $data == null since undefined (no “data” field) == null Use to check both a property in JSON data is store null value or not this property name
in – equal to a member	{“$gender”:[“male”, ”female”]}	{“gender”:”male”}	true	“male” in [“male”, “female”]
not	{“!$data”:100}}	{“data”:100}	false	data !== 100 reference a property in JSON object using !${name} for native value (not array, object)
not null	{“!$data”:null }	{“data”:100} {“data2”:100}	true false	data != null data != null => false, no data property reference a property in JSON object using !${name} for null value
not in	{“!$age”:[15,25,35,45]}	{“age”:16 }	true	age not in [15,25,35,45]

Operators

comparison operators

operator	JSON expression	JSON data to evaluate	Result in native true or false	note
equal	{“$data”:100} {“equal”:[ {“type”:”date.weekday”, “name”:”$today”}, “Monday” ] } {“equal”:[ {“type”:”date.weekday”, “name”:”$today”}, {“type”:”date.weekday”, “name”:”birthday”}, “Thursday”] } {“equal”:[1,1,1]}	{“data”:100} Today:”2022-10-06” {“birthday”:”2022-10-13”} Today:”2022-10-06”	True false true true	data === 100 it’s Thursday “Thursday” ==”Thursday” ==”Thursday” The day of birthday and today are Thursday 1==1==1
equal null	{“$data”:null}	{“data”:null} {“abc”:123}	true true	data === null data === null since undefined (no “data” field) === null
greater than	{“$age”: {“greater”:18}} {“greater”:[18,25]} {“greater”:[25,10,1]}	{“age”:25}	true false true	age > 25 18 > 25 25>10>1
less than	{“$age”: {“less”:40} {“less”:[25,10,11]}	{“age”:50}	false false	Age < 50 25<10<11
greater than or equal	{“$name”: {“greaterOrEqual”:”Apollo” }} { “greaterOrEqual”:[25,10,10]}	{“name”:”apollo”}	false true	name >= “apollo” 25>=10>=10
less than or equal	{“$birthday”: {lessOrEqual:”2000-01-01” }} { “lessOrEqual”:[25,50,10]}	{“birthday”:”1999-12-31”}	true false	birthday >= “2000-01-01” 25<=50<=10
between Must always have 2 values in array	{“lessOrEqual”: [15,{ name,“BTSfare”},59]}	{“BTSfare”:59}	true	BTSfare >=15 && BTSfare <=59
in – equal to a member	{“$gender”:[“male”,”female”]} {“in”:{“name”:”gender”,”values”:[ “male”,”female”]} {“in”:{“value”:”male”,”values”:[ “male”,”female”]}	{“gender”:”male”} {“gender”:”male”}	true true true	“male” in [“male”, “female”] “male” =”male”
not null	{“!$data”:null }	{“data”:100} {“data2”:100}	true false	data != null data != null => false, no data property
not in	{“!$age”:[15,25,35,45]} {“notin”:{“name”:”age”,”values”: [15,25,35,45]} {“notin”:{“value”:25,”values”: [15,25,35,45]}	{“age”:16 } {“age”:16 }	true true false	age not in [15,25,35,45] age != 15, age != 25, age != 35, age != 45 25 not in [15,25,35,45]

Logical operators

operator	JSON expression	JSON data to evaluate	Result in native true or false	note
and	{and:[true,true,true,{“$data”:100}]}	{“data”:100}	True	true && true && true && true
or	{or:[false,false,false,{“$data”:100}]}	{“data”:100}	true	false || false || false || true
not	{“!$data”:100}} {“not”:{“name”:”is_good”}} {“not”:{“$data”:100}} {“not”:[true,false,1,2,0,null]} {“not”:{“name”:”data” } }	{“data”:100} { “is_good”:false } {“data”:100} {“data”: [true,false,1,2,0,null]}	false true false [false, true, false, false, true, true] [false, true, false, false, true, true]	data !== 100 !false !(data === 100) [!true, !false, !1, !2, !0, !null] [!true, !false, !1, !2, !0, !null]

TYPE Conversion

Boolean

Boolean native value still represents as true, false

operator	JSON expression	JSON data to evaluate	Result in native true or false	note
return boolean	{“type”:”boolean” “name”: “is_thai” }	{“is_thai”: true} {“is_thai”: false} {“is_thai”: 1} {“is_thai”: 0} {“is_thai”: “text”}	true false true false false	1 == true 0 == true “text”== true
return boolean value	{“type”:”boolean”, “value”: true } {“type”:”boolean”, “value”: false } {“type”:”boolean”, “value”: 0 } {“type”:”boolean”, “value”: 1 } {“type”:”boolean”, “value”: 11.1 } {“type”:”boolean”, “value”: null }		true false false true false false	0 == true 1 == true 11.1 == true null == true
not the day in week	{“not”:{“equal”:[ {“type”:”date.weekday”}, ”name”:”birthday”}, “Monday” ]}}	{“birthday”:”2022-10-06” }	true	Birthday is not Monday. It’s “Thursday”.

Date

Date type in JSON expression

case	JSON expression	JSON data to evaluate	Result always in date instance	note
return date	{“type”:”date”, “name”:”birthday”} {“type”:”date”, “value”:”$today”} {“type”:”date”, “value”:”$now”}	{“birthday”:”2002-01-01” } {“birthday”: 1665033868536} {“birthday”: 0} {“aday”:1000} {“birthday”:”Not a day”} today:”2022-10-06” now:”2022-10-06 13:01:01.599”	“2002-01-01 00:00:00.000” “2022-10-06T05:24:28.536Z” “1970-01-01T00:00:00.000Z” “1970-01-01T00:00:00.000Z” “Invalid Date” ”2022-10-06” Return special field today’s value ”2022-10-06 13:01:01.599” Return special field now’s value	date will treat as local time e.g. “2002-01-01” will not treat as 00:00 in UTC time as Date in Javascript “$today”can be used to reference today date without time, “$now” can be used to reference current datetime. Both cannot use outside of “type”:”date” e.g., {“$today”:100} Mean reference value of JSON property name “today”
return date value	{“type”:”date”, “value”:”2022-01-01”} {“type”:”date”, “value”: 1665033868536} {“type”:”date”, “value”: “Not a date”}		“2002-01-01 00:00:00.000” {“birthday”: 1665033868536}	See JavaScript Date Objects (w3schools.com) Throw error, does not allow value that cannot convert to date
Modify date	{ “type”:”date”, “name”:”birthday”, “add”:{ “day”:15, “year”:1, “hour”:1 } } { “type”:”date”, “name”:”birthday”, “subtract”:{ “day”:15, “year”:1, “hour”:1 } }	{“birthday”:”2002-01-01” } {“birthday”:”2002-01-16 05:00” }	“2003-01-16 01:00:00.000” “2001-01-01 04:00”	Support “day”, “month”, ”year”, “hour”, “minute”, “second”
Before	{“greater”: [ {“type”:”date”, “name”:“expire_date”}, {“type”:”date”, “value”:”$today”} ] } {“greater”: [ {“type”:”date”, “name”:“expire_date”}, {“type”:”date”, “value”:”$today”, “add”:{ “day”:15 } } ] }	{“expire_date”:”2222-12-01” } today:”2022-10-06” {“expire_date”:”2022- 10-15” } today:”2022-10-06” today + 15: “2022-10-21	true False	Before expire date Today < expire_date – 15 == expire_date > today + 15
within 15 days before expired	{ “lessOrEqual”: [ {“type:”date”, “value”:”$today”}, {“type”:”date”, “name”:“expire_date”}, {“type”:”date”, “value”:”$today”, “add”:{ “day”:15 } } ] }	{“expire_date”:”2022- 10-15” } {“expire_date”:”2022- 10-01” } {“expire_date”:”2022- 10-21” } today:”2022-10-06” between: [“2022-10-06”, “2022-10-21”]	true false true	expired before today start of the period

Part of date

Case	JSON expression	JSON data to evaluate	Result in number except weekday (string)	note
day in week 1-7 Sunday=1 Monday=2 … Saturday=7	{type:”date.day”, “name”:”birthday”}	{“birthday”:”2002-01-01” } {“birthday”:”Not a day”}	2 NaN	date will treat as local time e.g. “2002-01-01” will not treat as 00:00 in UTC time as Date in Javascript
Weekday “Sunday”, “Monday”, “Tuesday”, … “Saturday”	{“type”:”date.weekday”, “name”:”birthday”}	{“birthday”:”2022-10-06” } {“birthday”:”Not a day”}	“Thursday” null
Date of month	{“type”:”date.date”, “name”:”birthday”}	{“birthday”:”2022-10-06” } {“birthday”:”Not a day”}	6 NaN
Month of year	{“type”:”date.month”, “name”:”birthday”}	{“birthday”:”2022-10-06” } {“birthday”:”Not a day”}	10 NaN
Date of month	{“type”:”date.year” “name”:”birthday”}	{“birthday”:”2022-10-06” } {“birthday”:”Not a day”}	2022 NaN
Hour of day	{“type”:”date.hour” “name”:”birthday”}	{“birthday”:”2022-10-06 21:00” } {“birthday”:”Not a day”}	21 NaN
Minute of hour	{“type”:”date.minute” “name”:”birthday”}	{“birthday”:”2022-10-06 21:00” } {“birthday”:”Not a day”}	00 NaN
Second of minute	{“type”:”date.secord” “name”:”birthday”}	{“birthday”:”2022-10-06 21:00:12” } {“birthday”:”Not a day”}	12 NaN
Birthday is 25th	{“target_date”:{“type”:”date.date” “name”:”birthday”}}	{target_date:25, “birthday”:”2022-10-06 21:00:12”}	false
Every birthday’s month	{“equal”:[{type:”date.month”, “name”:”birthday”}, {“type”:”date.month”, “value”:”$today”}]}