Utilize regular expressions on a JSON response dataset

Question

Utilize regular expressions on a JSON response dataset

Imagine a scenario where a client makes a GET request and the response is in JSON format similar to the following:

     var result = {
    "enabled": true,
    "state": "schedule",
    "schedules": [
        {
        "rule": {
        "start": "2014-06-29T12:36:26.000",
        "end": "2014-06-29T12:36:56.000",
        "recurrence": [
        "RRULE:FREQ=MINUTELY"
        ]
        },
        "wifi_state_during_rule": "disabled",
        "end_state": "enabled"
        }
    ],
    "calculated_wifi_state_now": "disabled",
    "time_of_next_state_change": [
        "2014-07-08T18:56:56.000Z",
        "2014-07-08T18:57:56.000Z"
    ]
};

This example stores the JSON response in a variable named "result". The regex expression used here is:

checkPattern = /"\w+\"(?=:)/ // Extracts all keynames "keyname": ...

The idea is to extract keynames within the object or array structure of the JSON data. Since keynames are defined as "keyname": in JSON, that's why this specific regex expression is being utilized.

Although a recursive function was considered for this task, it did not yield the desired results.

javascript json regex

Answer 1

Answer №1

It's best practice to avoid using regular expressions to parse irregular structures.

Instead, extract the desired information from a parsed JSON object.
To do this, simply execute data = JSON.parse(json_string)

function getKeysRecursive(obj) {
  var result = [];
  for (var key in obj) {
    result.push(key);
    if (typeof obj[key] == 'object') {
       result = result.concat(getKeysRecursive(obj[key]));
    }
  }
  return result;
}

getKeysRecursive(({
    "enabled": true,
    "state": "schedule",
    "schedules": [
        {
        "rule": {
        "start": "2014-06-29T12:36:26.000",
        "end": "2014-06-29T12:36:56.000",
        "recurrence": [
        "RRULE:FREQ=MINUTELY"
        ]
        },
        "wifi_state_during_rule": "disabled",
        "end_state": "enabled"
        }
    ],
    "calculated_wifi_state_now": "disabled",
    "time_of_next_state_change": [
        "2014-07-08T18:56:56.000Z",
        "2014-07-08T18:57:56.000Z"
    ]
}))

// ["enabled", "state", "schedules", "0", "rule", "start", "end", "recurrence", "0", "wifi_state_during_rule", "end_state", "calculated_wifi_state_now", "time_of_next_state_change", "0", "1"]

You have the flexibility to filter, sort, and exclude numeric keys as needed.

Answer 2

It's best practice to avoid using regular expressions to parse irregular structures.

Instead, extract the desired information from a parsed JSON object.
To do this, simply execute data = JSON.parse(json_string)

function getKeysRecursive(obj) {
  var result = [];
  for (var key in obj) {
    result.push(key);
    if (typeof obj[key] == 'object') {
       result = result.concat(getKeysRecursive(obj[key]));
    }
  }
  return result;
}

getKeysRecursive(({
    "enabled": true,
    "state": "schedule",
    "schedules": [
        {
        "rule": {
        "start": "2014-06-29T12:36:26.000",
        "end": "2014-06-29T12:36:56.000",
        "recurrence": [
        "RRULE:FREQ=MINUTELY"
        ]
        },
        "wifi_state_during_rule": "disabled",
        "end_state": "enabled"
        }
    ],
    "calculated_wifi_state_now": "disabled",
    "time_of_next_state_change": [
        "2014-07-08T18:56:56.000Z",
        "2014-07-08T18:57:56.000Z"
    ]
}))

// ["enabled", "state", "schedules", "0", "rule", "start", "end", "recurrence", "0", "wifi_state_during_rule", "end_state", "calculated_wifi_state_now", "time_of_next_state_change", "0", "1"]

You have the flexibility to filter, sort, and exclude numeric keys as needed.

Answer 3

Answer №2

You don't need to use a regular expression for this task. In JavaScript, there is a built-in function that allows you to extract the key names of an object.

For example:

Simply use Object.keys();

var data = {
    "enabled": true,
    "state": "schedule",
    "schedules": [
        {
            "rule": {
                "start": "2014-06-29T12:36:26.000",
                "end": "2014-06-29T12:36:56.000",
                "recurrence": [
                    "RRULE:FREQ=MINUTELY"
                ]
            },
            "wifi_state_during_rule": "disabled",
            "end_state": "enabled"
        }
    ],
    "calculated_wifi_state_now": "disabled",
    "time_of_next_state_change": [
        "2014-07-08T18:56:56.000Z",
        "2014-07-08T18:57:56.000Z"
    ]
};

Then, use:

console.log(Object.keys(data));

This should output:

["enabled", "state", "schedules", "calculated_wifi_state_now", "time_of_next_state_change"]

Proof: http://codepen.io/theConstructor/pen/zBpWak

Now all your object keys are neatly stored in an array.

I hope this information proves helpful to you.

Answer 4

You don't need to use a regular expression for this task. In JavaScript, there is a built-in function that allows you to extract the key names of an object.

For example:

Simply use Object.keys();

var data = {
    "enabled": true,
    "state": "schedule",
    "schedules": [
        {
            "rule": {
                "start": "2014-06-29T12:36:26.000",
                "end": "2014-06-29T12:36:56.000",
                "recurrence": [
                    "RRULE:FREQ=MINUTELY"
                ]
            },
            "wifi_state_during_rule": "disabled",
            "end_state": "enabled"
        }
    ],
    "calculated_wifi_state_now": "disabled",
    "time_of_next_state_change": [
        "2014-07-08T18:56:56.000Z",
        "2014-07-08T18:57:56.000Z"
    ]
};

Then, use:

console.log(Object.keys(data));

This should output:

["enabled", "state", "schedules", "calculated_wifi_state_now", "time_of_next_state_change"]

Proof: http://codepen.io/theConstructor/pen/zBpWak

Now all your object keys are neatly stored in an array.

I hope this information proves helpful to you.

Answer 5

Answer №3

Using this regular expression will extract all the keys from the given text:

\"(\w+)(?:\"\:)

https://regex101.com/r/eK7sF9/4

This modification allows the regex to handle multiple keys on a single line.

Answer 6

Using this regular expression will extract all the keys from the given text:

\"(\w+)(?:\"\:)

https://regex101.com/r/eK7sF9/4

This modification allows the regex to handle multiple keys on a single line.

Utilize regular expressions on a JSON response dataset

Answer №1

Answer №2

Answer №3

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