如何从javascript中的字符串中提取json

Question

I need to extract json from a particular string which looks like this:

'loglocale=
{
    "seed": "pqr",
    "pageHashCode": "xxx",
    "timestamp": 1553589859880,
    "channel": "mobile",
    "serviceVersion": "1.0",
    "language": "en-CHN"
}
; regStatus=xx; s_dslv=34; s_fid=65-64748; s_vn=64678%26vn%3D1',
  groups: undefined ]

I have tried this but could not extract it .

var regex=cookies.match(/{"seed":(\w|\W)*"channel":(\w|\W)*}/);

What is the solution I could use? Thanks in advance:)

Answer 1

For the loglocale:

let dataJSON = `
'loglocale=
{
    "seed": "pqr",
    "pageHashCode": "xxx",
    "timestamp": 1553589859880,
    "channel": "mobile",
    "serviceVersion": "1.0",
    "language": "en-CHN"
}
; regStatus=xx; s_dslv=34; s_fid=65-64748; s_vn=64678%26vn%3D1',
  groups: undefined ]`

then:

let string = dataJSON.substring(
       dataJSON.indexOf("loglocale=") + 10, 
       dataJSON.lastIndexOf("; regStatus")
   )
JSON.parse(string);

Answer 2

If you know there is only a single plain JSON object like this in the string, you can use this regex to capture the curly braces and everything in between:

const curlyBracesInclusive = /\{([^}]+)\}/
const arr = string.match(curlyBracesInclusive)
// arr[0] will be a the JSON string, if one was found

This is no way guarantees the string is valid JSON. So if you want to run JSON.parse on the result, be aware it will throw an error if the string is invalid.