JSON.parse 不会解析数组？

Question

Here's a code snippet that's been throwing me for a loop:

var _tids = [];
console.log("type:", typeof user._imported_readTids, "value:", user._imported_readTids);
try {
    _tids = JSON.parse(user._imported_readTids);
} catch(e) {
    return nxt();
}

console.log("user:", user.uid, "type:", typeof _tids, "\narray:", _tids);

in the first console.log , the type of the field _imported_readTids is a string, which is expected (a string representation of an array, like "[1,2,3]" (no spaces between elements))

When I call JSON.parse on that string, I'm expecting it to be turned into an array, but on the second console.log , the type is still a string, and the array representation looks the same.

Here's the output:

// first console.log (truncated for brevity):
type: string value: "[4,5,6,7,8,...,234]"

// second: 
user: 1 type: string 
array: [4,5,6,7,8,...,234]

I've tried these same params and used in a console nodejs process, and it comes out as expected, typeof jsonArray will return 'object' .

This is in NodeJS, v0.12.5, OSX 10.11.1 (El capitan)

Answer 1

The first time you console.log it says that the string value starts and end with a " .

The second time, it does not say that.

You have a string representation of a JSON text which itself consists of a string representation of a JSON text which is an array.

After you parse it, you have a string representation of a JSON text which is an array.

ie Your array is double stringified, so you need to parse it twice (or fix whatever is encoding it in the first place so it only does it once).

Answer 2

If you make this change on the php side, it will be solved. example: $x=[a,b,x]; $x2=array();

$x2[]=$x;

echo json_encode($x2);