How do I output a javascript array where each array item is a new line using JSON.stringify

Question

My goal is to take a javascript array object and output it to a string formatted in a way I can store it in a file. I want to use JSON.stringify because it's a lot more robust than my own function will be. If I have to I can just use a new function for it.

I have an array with multiple objects say [{"attr1":"val", "attr2":"val", "attr3":"val"}, {"attr1":"val", "attr2":"val", "attr3":"val"}, {"attr1":"val", "attr2":"val", "attr3":"val"}, ...] I need to store this in a text file in the format of

[{"attr1":"val", "attr2":"val", "attr3":"val"},
 {"attr1":"val", "attr2":"val", "attr3":"val"}, 
 {"attr1":"val", "attr2":"val", "attr3":"val"}, 
 ...]

I know I can pretty print with JSON.stringify, but it prints each attribute on a new line instead of printing each array item on a newline.

tex · Accepted Answer · 2020-01-09 01:28:08Z

4

Here's a one-liner:

const data = [{"attr1":"val", "attr2":"val", "attr3":"val"},{"attr1":"val", "attr2":"val", "attr3":"val"},{"attr1":"val", "attr2":"val", "attr3":"val"}]
 
const formatted = `[${data.map(JSON.stringify).join(',\n ')}]`
 
console.log(formatted)

edited Jan 9, 2020 at 1:28

answered Jan 9, 2020 at 1:05

tex

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2 Comments

junwen-k Over a year ago

You might want to add an extra spacing right after \n to further improve the formatting of the JSON. ( Align new object item with the beginning square bracket )

tex Over a year ago

Done! Thanks for the suggestion.

solimanware · Accepted Answer · 2020-01-09 00:45:31Z

1

You need to store every object of array in new line first, to do this you can do this simple loop:

const arr = [{ "attr1": "val", "attr2": "val", "attr3": "val" },
{ "attr1": "val", "attr2": "val", "attr3": "val" },
{ "attr1": "val", "attr2": "val", "attr3": "val" }]

let text = '';
for(let obj of arr){
    text += JSON.stringify(obj) + '\n'
}
console.log(text);

answered Jan 9, 2020 at 0:45

solimanware

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1 Comment

solimanware Over a year ago

you may beed to add comma after every object or as you like the print to be

Colin Keenan · Accepted Answer · 2023-10-07 12:47:54Z

0

The accepted answer, produced typescript errors for me, and I also don't want "\n" after the last element. Here's what gave the output I wanted:

const arr = [{ "attr1": "val", "attr2": "val", "attr3": "val" },
{ "attr1": "val", "attr2": "val", "attr3": "val" },
{ "attr1": "val", "attr2": "val", "attr3": "val" }];
const [a0, ...aRest] = arr;
const formattedArr = `[${JSON.stringify(a0)},${aRest.map( (a) => "\n" + JSON.stringify(a) )}]`;
console.log(formattedArr);

answered Oct 7, 2023 at 12:47

Colin Keenan

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