For my latest app I wanted to be able to code the front-end first, without having to do super extensive documentation and without forgetting my data types later on while coding the back-end. I thus tried to make some kind of JSON Validator that expects something and outputs true or false depending on the input fed to it. (Meaning that I can define my data structures that way)
What I have works, but I'm not sure if that was the right way to go. Any comments?
export class ArrayValidator { /** * Array-Template Syntax: * { * "layer_type": "object"|"array"|"value", (if array): "items": -1, "item": {"layer_type": ...} (end if array) (if value) "value": 'regexp' (end if value) (if object) "properties": [ { "name": "string", "null_allowed": true|false, "value": {"layer_type": etc ...} }, {...} ] (end if object) * } **/ public static testUpon(arrayToTest, arrayTemplate) : boolean { if(arrayTemplate.layer_type == "object"){ for(let prop of arrayTemplate.properties){ if(arrayToTest[prop.name] == null && prop.nullAllowed == 'false'){ console.log("[ArrayValidator][Error]Nonexistent property: " + prop.name); return false; } if(arrayToTest[prop.name] != null && !ArrayValidator.testUpon(arrayToTest[prop.name], prop.value)) return false; } }else if(arrayTemplate.layer_type == "array"){ if(arrayTemplate.items!=-1 && arrayToTest.length != arrayTemplate.items){ console.log("[ArrayValidator][Error]Array of wrong length."); return false; } for(let item of arrayToTest){ if(!ArrayValidator.testUpon(item, arrayTemplate.item)) return false; } }else if(arrayTemplate.layer_type == "value"){ let regexp = new RegExp(arrayTemplate.value); let res = regexp.test(arrayToTest); if(!res) console.log("[ArrayValidator][Error]Value Regexp doesn't match. [Regexp: " + arrayTemplate.value + ", Value: " + arrayToTest + "]"); return res; } return true; } public static test(){ let template = JSON.parse('{"layer_type": "object", "properties": [{"name": "obj", "nullAllowed": "false", "value": {"layer_type": "object", "properties": []}}, {"name": "embed", "nullAllowed": "false", "value": {"layer_type": "array", "items": -1, "item":{"layer_type": "value", "value": "(.+?)"}}}, {"name": "testVal", "nullAllowed": "false", "value": {"layer_type": "value", "value": "^[A-Za-z]+$"}}]}'); let test = JSON.parse('{"testVal": "Hello", "embed": ["test", "another test", 24], "obj": {}}'); console.log("Output: " + ArrayValidator.testUpon(test, template)); } } 
