This means that array indexes start at 0 and go up to the number of elements, minus 1. JavaScript for loops iterate over each item in an array. It sounds like the data structure is confusing :-) If you have an object with unknown/random property names, you can't really access a specific property without knowing the name. The following example illustrates this behavior. You are going to need be be defensive in the way that you reference your property. – Strille Oct 3 '13 at 9:04 You could use a computed property JavaScript arrays are zero based, which means the first item is referenced with an index of 0. The syntax to access an array member Looping Through an Array. Creating an Array Using an array literal is the easiest way to create a JavaScript Array. By default the indexing of every JavaScript array starts from 0. I recommend using $.ajax() and specifying the dataType as JSON, or using $.getJSON(). let arr = Array (9.3) // RangeError: Invalid array length. Calling Array(N) results in a RangeError, if N is a non-whole number whose fractional portion is non-zero. The Basic For Loop. If your code needs to create arrays with single elements of an arbitrary data type, it is safer to use array … The items property is accessed as follows: data.items The value is an array, to access its second element, we have to use bracket notation: data.items[1] This value is an object and we use dot notation again to access the name property. The problem most likely is that the value is undefined at some point in the components lifecycle (you're probably loading it asynchronously). Remember that the index values start at 0, not 1. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Referencing items in arrays is done with a numeric index, starting at zero and ending with the array length minus 1. In the above example, we removed seahorse from the array, and pushed a new value into index 3. Here is an example that demonstrates $.ajax() and shows you how to access the returned values in an array. An “indexed” array is one where the index must be an integer, and you access its elements using its index as a reference. An array can hold many values under a single name, and you can access the values by referring to an index number. As we saw, arrays can have several dimensions, which means that an array element can contain an array, whose elements can contain arrays, etc. I ask because when you find yourself trying to circumvent one of the most basic characteristics of a programming language, odds are good there's a better way to do what you're trying to do. It would help to know what your AJAX request looks like. Here’s an example of an indexed array: Here’s an example of … It's not like an array where you can access a value by index ("pick the first value"). 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