How to Convert String of Objects to Array in JavaScript ?

Last Updated : 30 Aug, 2024
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This article will show you how to convert a string of objects to an array in JavaScript. You have a string representing objects, and you need to convert it into an actual array of objects for further processing. This is a common scenario when dealing with JSON data received from a server or stored in a file.

Table of Content

Using JSON.parse() Method

The most common and straightforward way to convert a string of objects to an array of objects is by using JSON.parse() method. This method parses a JSON string into a JavaScript object or array.

Example: This example shows the use of the above-mentioned approach.

JavaScript 
let str = '[{"company":"Geeks", "contact":"+91-9876543210"}, 
  {"address":"sector 136", "mail":"xys@geeksforgeeks.org"}]';
let arr = JSON.parse(str);

console.log(arr);

Output
[
  { company: 'Geeks', contact: '+91-9876543210' },
  { address: 'sector 136', mail: 'xys@geeksforgeeks.org' }
]

Using eval() Method

Another approach to convert a string of objects to an array is by using the eval() function. However, this method is generally not recommended due to security risks associated with executing arbitrary code.

Example: This example shows the use of the above-explained approach.

JavaScript 
let str = '[{"company":"Geeks", "contact":"+91-9876543210"}, 
  {"address":"sector 136", "mail":"xys@geeksforgeeks.org"}]';

let arr = eval(str);

console.log(arr);

Output
[
  { company: 'Geeks', contact: '+91-9876543210' },
  { address: 'sector 136', mail: 'xys@geeksforgeeks.org' }
]

Using the Function Constructor

Another method to convert a string of objects to an array of objects is by using the Function constructor. This method is safer than eval() as it creates a new function and doesn't have access to the local scope.

Example: This example shows the use of the Function constructor to convert a string of objects to an array of objects.

JavaScript 
let str = '[{"company":"Geeks", "contact":"+91-9876543210"}, {"address":"sector 136", "mail":"xys@geeksforgeeks.org"}]';
let arr = (new Function('return ' + str))();

console.log(arr);

Output
[
  { company: 'Geeks', contact: '+91-9876543210' },
  { address: 'sector 136', mail: 'xys@geeksforgeeks.org' }
]

By Spliting JSON into Components

This method splits the JSON string into components and reconstructs the objects. It is a more manual approach and assumes that the JSON string is well-formed and simple.

Example:

JavaScript 
function parseStringToArrayOfObjects(str) {
    // Remove surrounding brackets and extra spaces
    str = str.trim().slice(1, -1).trim();
    const objectStrings = str.split(/(?<=\}),\s*(?=\{)/);
    let result = [];
    function parseObjectString(objectStr) {
        // Remove leading and trailing spaces and curly braces
        objectStr = objectStr.trim().slice(1, -1).trim();

        // Initialize the object
        let obj = {};
        let key = '';
        let value = '';
        let inKey = true;
        let inString = false;
        let isEscaped = false;

        for (let i = 0; i < objectStr.length; i++) {
            let char = objectStr[i];

            if (char === '\\') {
                // Handle escaped characters
                isEscaped = !isEscaped;
                value += char;
                continue;
            }

            if (char === '"' && !isEscaped) {
                inString = !inString;
                if (!inString) {
                    if (inKey) {
                        key = value;
                    } else {
                        obj[key] = value;
                    }
                    value = '';
                    inKey = !inKey;
                }
                continue;
            }

            if (inString) {
                value += char;
            } else if (char === ':') {
                inKey = false;
            } else if (char === ',') {
                if (!inKey) {
                    obj[key] = value;
                    value = '';
                    inKey = true;
                }
            } else if (char === ' ' || char === '\n' || char === '\t') {
                // Ignore whitespace
                continue;
            } else {
                value += char;
            }

            isEscaped = false;
        }

        if (key && !inKey) {
            obj[key] = value;
        }

        return obj;
    }

    // Parse each object string and add it to the result array
    for (let objectStr of objectStrings) {
        result.push(parseObjectString(objectStr));
    }

    return result;
}

const str = '[{"company":"Geeks", "contact":"+91-9876543210"}, {"address":"sector 136", "mail":"xys@geeksforgeeks.org"}]';

const arr = parseStringToArrayOfObjects(str);

console.log(arr);

Output
[
  { company: 'Geeks', contact: '+91-9876543210' },
  { address: 'sector 136', mail: 'xys@geeksforgeeks.org' }
]



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