CODEWITHSUNDEEP
javascriptjson
user8758206
user8758206

Reputation: 2191

Converting a String to Multiple objects (javascript)

I have the following string: Jack:13,Phil:15,Lucy:12I'm trying to fetch objects from this string.

This string would have 3 people objects with their ages. How can this be achieved?

I've tried the following:

var s = 'Jack:13,Phil:15,Lucy:12'

var obj1 = eval("("+s+")");
var obj2 = JSON.parse(s);

Logging any of the obj variables returns errors. Am I missing a simple trick here? Any explanation would be appreciated, thanks.

Upvotes: 0

Views: 1171

Answers (6)

T.J. Crowder
T.J. Crowder

Reputation: 1074505

In general, if you're doing replaces on a string to turn it into something you can pass eval or JSON.parse, that's probably not your best approach. An in particular, avoid using eval (or its cousin new Function) when you can (you certainly can here), and always avoid eval (or its cousin new Function) with untrusted input.

A pair of splits with map does it:

const s = 'Jack:13,Phil:15,Lucy:12'
const people = s.split(",")
  .map(e => e.split(":"))
  .map(([name, age]) => ({name, age}));
console.log(people);

...or in ES5:

var s = 'Jack:13,Phil:15,Lucy:12'
var people = s.split(",")
  .map(function(e) { return e.split(":"); })
  .map(function(e) { return {name: e[0], age: e[1]}; });
console.log(people);

I'm not sure why I did two maps rather than just doing the second split and creating the object in the same callback; I guess I'm thinking more and more in a "functional programming" way. I'd change it, but Eddie's answer already does it in a single map, so...

...(edit) but since it looks like you wanted separate properties rather than using the person's name like Eddie did, here's an example of the above but with just a single map:

const s = 'Jack:13,Phil:15,Lucy:12'
const people = s.split(",")
  .map(e => {
    const [name, age] = e.split(":");
    return {name, age};
  });
console.log(people);

...or in ES5:

var s = 'Jack:13,Phil:15,Lucy:12'
var people = s.split(",")
  .map(function(e) {
    var parts = e.split(":");
    return {name: parts[0], age: parts[1]};
  });
console.log(people);

Upvotes: 3

Andrew Bone
Andrew Bone

Reputation: 7291

As I'm sure you've worked out there are many ways to do this, I thought I'd add another method

let s = 'Jack:13,Phil:15,Lucy:12'
let obj = {};

s.split(",").forEach(part => {
  obj[part.split(":")[0]] = part.split(":")[1];
})
console.log(obj);

This is a simple split the string and then on each item of the new array do a split and push the results into an empty object already declared.

Upvotes: 2

Samuli Hakoniemi
Samuli Hakoniemi

Reputation: 19049

Easy to do with .map():

var s = 'Jack:13,Phil:15,Lucy:12';
var items = s.split(',')
    .map((entry) => entry.split(':'))
    .map((item) => ({name: item[0], age: item[1]}));

console.log(items);

Upvotes: 1

hsz
hsz

Reputation: 152226

You can try with:

const result = s.split(',')
  .map(value => value.split(':'))
  .reduce((acc, [name, value]) => {
    acc[name] = +value;
    return acc;
  }, {});

Output:

{
  "Jack": 13,
  "Phil": 15,
  "Lucy": 12
}

Upvotes: 2

Nina Scholz
Nina Scholz

Reputation: 386654

You could split the parts and build a new object with key/value pairs.

var string = 'Jack:13,Phil:15,Lucy:12',
    result = Object.assign(...string
        .split(',')
        .map(s => (([k, v]) => ({ [k]: v }))(s.split(':')))
    );
        
console.log(result);

For getting an array with objects

var string = 'Jack:13,Phil:15,Lucy:12',
    result = string
        .split(',')
        .map(s => (([name, age]) => ({ name, age }))(s.split(':')));
        
console.log(result);

Upvotes: 1

Eddie
Eddie

Reputation: 26844

You can split() the string and use map() to loop thru the array. This will return an array of objects.

var s = 'Jack:13,Phil:15,Lucy:12';

var result = s.split(',').map(o => {
  let [k, v] = o.split(':');
  return {[k]: v};
});

console.log(result);

If you want a single object, you can use reduce

var s = 'Jack:13,Phil:15,Lucy:12';

var result = s.split(',').reduce((c, o) => {
  let [k, v] = o.split(':');
  return Object.assign(c, {[k]: v});
}, {});

console.log(result);

Upvotes: 2

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