This content originally appeared on Christian Heilmann and was authored by Chris Heilmann
You can use `JSON.stringify()` to turn a JSON object into a string.
let obj = {“a”: 1, “b”: 3, “c”: “boo!”};
console.log(JSON.stringify(obj))
This results in a single line string:
{a!”}
However, you can also set two optional parameters, a filtering array or callback method and an indentation parameter. Setting the indentation to four, for example, creates a multi line string with 4 spaces indentation:
let obj = {“a”: 1, “b”: 3, “c”: “boo!”};
console.log(JSON.stringify(obj, false, 4))
Output:
{
“a”: 1,
“b”: 3,
“c”: “boo!”
}
If instead of spaces you want tabs, you can also defined the indentation parameter as a string:
let obj = {“a”: 1, “b”: 3, “c”: “boo!”};
console.log(JSON.stringify(obj, false, “t”))
Output:
{
“a”: 1,
“b”: 3,
“c”: “boo!”
}
Or any other string:
let obj = {“a”: 1, “b”: 3, “c”: “boo!”};
console.log(JSON.stringify(obj, false, “xxx”))
Output:
{
xxx”a”: 1,
xxx”b”: 3,
xxx”c”: “boo!”
}
You can define an array of keys you want to show to filter the outcome:
let obj = {“a”: 1, “b”: 3, “c”: “boo!”};
console.log(JSON.stringify(obj, [‘a’,’c’], 4))
Output:
{
“a”: 1,
“c”: “boo!”
}
And you can write a filtering callback function that gets applied to the JSON object. For example, to only allow for numbers to show:
const onlyNumbers = (key,value) => {
return (typeof value === ‘string’) ? undefined : value
}
let obj = {“a”: 1, “b”: 3, “c”: “boo!”};
console.log(JSON.stringify(obj, onlyNumbers, 4))
Output:
{
“a”: 1,
“b”: 3
}
You can see more examples on MDN .
Whilst I like these options, it always feels weird to me when a method allows for different values to determine what to do. Having the replacer either be an array or a callback and the spaces option be a number or a string feels confusing. What do you think?
This content originally appeared on Christian Heilmann and was authored by Chris Heilmann
Chris Heilmann | Sciencx (2022-10-28T06:11:39+00:00) Reminder: JSON.stringify can create Multi-line, formatted and filtered strings from JSON. Retrieved from https://www.scien.cx/2022/10/28/reminder-json-stringify-can-create-multi-line-formatted-and-filtered-strings-from-json/
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