bobtail | lightweight CoffeeScript library/DSL for reactive | Reactive Programming library

I think it would be a good idea to have the data about what to select in an array/object.

I guess there are a lot of new stuff here, but notice especially that the data item is inserted into the option element as itemdata. This is a trick for passing around data.

There are a couple of issues I see on your code.

In your showbtn() function, your using the getElementsById function, but as far as I am aware, this doesn't exist. Were you trying to execute getElementsByName instead?

Either way, that would return a NodeList that you'd have to iterate over, and I see that you're trying to check the onchange, which in itself is an assignable property. That wouldn't work as expected.

I feel like you could simplify your logic by checking if at least one of your tags has a selected value that isn't "". Below is a simple suggestion - you can simplify if you want to by creating easier-to-select elements (either by names or class names, which would work with getElementsBy) // Array of select IDs. var arrayOfSelects = ['DHOps', 'LUOps', 'LTLOps', 'FEDEXOps']; // Iterate on each one. for (let select of arrayOfSelects) { var e = document.getElementById(select); // Checking if there is a selected value that isn't null, undefined, 0 or empty. if (e.value) { document.getElementById("submit").style.display = "block"; break; } }

Avoid redux state mutation to prevent bugs. Check out the Redux documentation for explanation and code examples: http://redux.js.org/docs/recipes/reducers/ImmutableUpdatePatterns.html#inserting-and-removing-items-in-arrays

Depending on your exact use case (like update / add / remove items) you could map over and compare every item using the array index, and add a boolean property like "isNew" on the order object. If you want to also check for updated items and if items can be removed then it would be better to use an object with unique IDs as the key to loop over every item.

You don't need to use local "state" on the order if you just want to render the className when updated from redux state, unless you also want to change it afterwards (like clicking it or removing the className again after a few seconds).

If you want to compare the whole object properties you could use utility methods like lodash.isEqual and lodash.omit to remove the "isNew" property before comparing to the new value, otherwise if you just want to add/remove items you can only compare the ID for example...

Didn't test this code but with using arrays of order objects and just checking if the object at the same position has the same ID to add "isNew" boolean value it would look something like this:

Typescript can not guarantee you that all the properties will be of type Cat. The object cats can have more properties than defined in the interface and their type is unknown at compile time. Only at runtime it can be determined which property the object has and what their type is.

You have three options to assert the type Cat: Type casts, type guards and hashmap types.

Type cast

When you are sure that all the properties of cats are of type Cat, you can simply cast your result into Cat: