Thus, they are treated as strings. The numbers Infinity and NaN , as well as the value null , are all considered null. The replacer parameter can be either a function or an array. It should return the value that should be added to the JSON string, as follows: If you return a Number , String , Boolean , or null , the stringified version of that value is used as the property's value. If you return a Function , Symbol , or undefined , the property is not included in the output. If you return any other object, the object is recursively stringified, calling the replacer function on each property.
The space argument may be used to control spacing in the final string. If it is a number , successive levels in the stringification will each be indented by this many space characters up to If it is a string , successive levels will be indented by this string or the first ten characters of it.
A string is an object, pure and simple. A string is an array of chars. The string class just creates a wrapper so developers won't tear their hairs off when trying to write full string sentences C language hmm A string is an object, reference type that behaves like a value type. Show 1 more comment. To get FirstName , you only use obj. Milan Chheda Milan Chheda 7, 3 3 gold badges 19 19 silver badges 35 35 bronze badges.
Stringify f — Md Ghousemohi. Add a comment. The Overflow Blog. Podcast Explaining the semiconductor shortage, and how it might end. Does ES6 make JavaScript frameworks obsolete?
Featured on Meta. However, when the return value is set to Function , Symbol , or undefined , the property will not be included in the output. This happens because these values are not supported for stringifying. Let us explore how to convert a function to a string in order to keep it in the stringified object:. In the example above, greet was added as a key to the user object, and its value set to function greet.
If so, it applies the toString method to it and returns the value to the calling method. Otherwise, the replacer will not make any changes to the value, letting stringify handle the data as it sees fit. Since greet is now a string , it can be stringified, thus it will be contained in the resulting JSON notation. This is due to the use of the space parameter. See the section on space below for more information. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content.
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