JSON to OData String for Query - json

Question

How can I turn a JSON object, i.e. { username: "john", password: "1234" } into an OData string query in a function using typescript? I could not find a library to do this for me (Angular 6). Here is my attempt:
function ConvertToODataString (json: Object) {
let ret_str: string = "";
for (let key in json) {
ret_str += (key + "=" + json[key] + "&");
}
if (ret_str) {
ret_str = ret_str.substr(0, ret_str.length - 1); // remove last &
}
return ret_str;
}
Does anyone know of a better way? For now, my json is not multi-leveled.

Answer 1

You can use for ... in to enumerate the object properties, adding each key/value pair to an array, and combine the values with Array.join:
function convertObjectToQuery(obj: Object): string {
let values = new Array<string>();
for (let prop in obj) {
values.push(`${prop} eq '${obj[prop]}'`);
}
return encodeURI("$filter=" + values.join(" and "));
}
See this stackblitz for a demo.

Answer 2

JSON.parse function.
Example:
var obj = JSON.parse('{ "name":"John", "age":30, "city":"New York"}');
json={ "name":"John", "age":30, "city":"New York"};
var obj = JSON.parse(json+'');

Answer 3

I decided to use the HttpParms module instead:
import { HttpParams } from "#angular/common/http";
const params = new HttpParams()
.set("$filter", "Username eq '" + parameters["Username"] + "' and Password eq '" + parameters["Password"] + "'")
.set("$count", "true");
console.log(params.toString());