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javascriptbrackets
Maarten Hartman
Maarten Hartman

Reputation: 1629

Use of square brackets in objects

my code has to be like this:

rules: {
  jform[name]: {
  required:true,
  minlength:5,
  maxlength:15
},

how should I use those square brackets? There are a lot of answers regarding this subject found on this website and on google, but not particularly for this one.

Upvotes: 0

Views: 7055

Answers (4)

zzzzBov
zzzzBov

Reputation: 179046

I can't accurately answer your question as it stands right now, because you're asking how to use invalid syntax, which is impossible as it's invalid.

However, what I can do is explain how JSON works in JavaScript and hope that it covers your problem:

The basics

{} is an object literal

//this creates a new object
a = {};
//so does this
a = new Object();

[] is an array literal

//this creates a new array
a = [];
//so does this
a = new Array();

properties can be accessed via . and [] notation:

//these are the same
a.b = c;
a['b'] = c;

Object literals can be set using literal values or strings:

a = {
    //any character you can use for a variable name can be
    //used to instantiate an object without quotes
    b: c,
    //special characters need to be quoted
    "foo bar baz": "fizz buzz"
};

Your original syntax of:

rules: {
  jform[name]: {
  required:true,
  minlength:5,
  maxlength:15
}

is invalid because you can't use [ and ] chars in a variable name, however you could use a string for the literal value:

rules: {
  "jform[name]": {
  required:true,
  minlength:5,
  maxlength:15
}

...which would be accessed as:

rules["jform[name]"]

but it appears that you want to access the data as:

rules.jform[name]

which would need to be set as:

rules: {
    jform: {}
}
...more code...
rules.jform[name] = {rules: {
    required:true,
    minlength:5,
    maxlength:15
};

Upvotes: 7

vireshas
vireshas

Reputation: 816

obj = {
 "rules" : {
  "jform" : {
    "name" : {
      required:true,
      minlength:5,
      maxlength:15
    }
   }
  }
},

you can now access values like this

 obj[rules][jform][name]

Upvotes: 3

gen_Eric
gen_Eric

Reputation: 227240

I'm guessing you want the value of jform[name] to a key in the object. You can't use variables as keys when declaring an object literal. You'll have to add this key as another statement.

Example:

var data = {
    rules: {
    }
};
data.rules[jform[name]]= {
    required:true,
     minlength:5,
     maxlength:15
};

If you want the key to literally be jform[name], then you need to use quotes around the key.

rules: {
    "jform[name]": {
        required:true,
        minlength:5,
        maxlength:15
    }
}

Upvotes: 3

Bergi
Bergi

Reputation: 664538

Do you mean JSON? Or JavaScript Object literals? Please remove the buzzword "jQuery" from your question.

If you want a property name with (square) brackets, you can either do

rules = {
  "jform[name]": {
    required:true,
    minlength:5,
    maxlength:15
  }
}

or

rules["jform[name]"] = {...};

Upvotes: 1

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