javascriptobjectobjectnameobject-notation

How to access javaScript object property NAME not VALUE

I have a an object
me = { name: "Mo", age: 28, } And I want to see if this object has the property "height" for example. (which it doesn't) How can i do this? So for example if it has the property "height" I can give it a value of "5,7".

PLEASE NOTE: I don't want to check for the property VALUE(me.name) but for the property NAME.

Thank you.

Solution

  • You can use the in operator:

    if ("height" in me) {
  // object has a property named "height"
}
else {
  // no property named "height"
}

    Note that if the object does not have a property named "height", you can still add such a property:

    me.height = 100;

    That works whether or not the object had a "height" property previously.

    There's also the .hasOwnProperty method inherited from the Object prototype:

    if (me.hasOwnProperty("height"))

    The difference between that and a test with in is that .hasOwnProperty() only returns true if the property is present and is present as a direct property on the object, and not inherited via its prototype chain.