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javascriptlocal-storagestringify

Why cannot I JSON.stringify localStorage

I tried this one 

JSON.stringify(localStorage, function(key, value) {
        console.log(key);
        return (key.split('.')[0] === 'SUWDdb') ? value : undefined;
})

and it only returns undefined, console only log one entries. can any one give me a reason and a solution?

Solution

  • Well, nothing at the top level satisfies your condition, and in that case your function is returning undefined, which means nothing below that is stringified. You probably want:

    JSON.stringify(localStorage, function(key, value) {
    console.log(key);
    return (typeof value === 'object' || key.split('.')[0] === 'SUWDdb') ? value : undefined;
            ^^^^^^^^^^^^^^^^^^^^^^^^^
})

    This will allow JSON.stringify to keep traversing downward when it encounters an object.