JSON to OData String for Query

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.

When you say "a JSON object", you start with the object instance or with the JSON string? — Martin Parenteau
– Martin Parenteau, Commented Oct 18, 2018 at 19:24
I think I probably need something more like $filter=username eq 'john' and password eq '1234'. — xinthose
– xinthose, Commented Oct 18, 2018 at 19:30

xinthose · Accepted Answer · 2018-10-18 19:54:10Z

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.

edited Oct 18, 2018 at 19:54

xinthose

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answered Oct 18, 2018 at 19:35

Martin Parenteau

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2 Comments

xinthose Over a year ago

Good idea, although I think my question should probably be worded differently because I am querying for these values, so I need the $filter operator and a different syntax.

Martin Parenteau Over a year ago

I modified the answer and the stackblitz according to your comments. Please edit the question if that is the format that you need.

David Tatis · Accepted Answer · 2018-10-18 19:19:03Z

0

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+'');

answered Oct 18, 2018 at 19:19

David Tatis

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2 Comments

xinthose Over a year ago

JSON.parse converts a string into an object, the opposite of what I need.

xinthose Over a year ago

Thank you for trying, but JSON.stringify will not format the string for OData querying.

xinthose · Accepted Answer · 2018-10-19 04:08:44Z

0

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());

answered Oct 19, 2018 at 4:08

xinthose

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