bug in step1-03,Extra brackets

[yinsang]

https://github.com/Microsoft/frontend-bootcamp/blob/master/step1-03/demo/README.md

const button = document.querySelector('.submit');
button.onclick = displayMatches();

It's wrong to add brackets after displayMatches.

[ahtee]

Can you go into further detail on why? Syntactically it makes sense that displayMatches is a function when including parentheses() and variables or constants can be quickly seen as such because they wont have parentheses()

[ecraig12345]

@yinsang Good catch, thanks!

@ahtee JavaScript has first-class functions, meaning that functions can be assigned to variables or passed as parameters the same as any other object or value. In this case, what we want to do is set the displayMatches function itself (not the return value from calling it) to be the button's onclick handler. The button will call displayMatches later, when it's clicked.

I don't think the step text should go into all that detail (unless it turns out to be a common point of confusion), but I updated the wording a bit to hopefully clarify what's going on.

In our example, we want to trigger a function when a button is clicked. To do this, we first need to get a reference to the button. We can use the querySelector method of the browser-provided document global variable to get that reference. Then we can set our displayMatches function to be the button's onclick handler.

[micahgodbolt]

fixed in #98