Added article on JSHint latedef option

Author: James Allardice

option-articles/latedef-jshint.md

@@ -0,0 +1,69 @@
+<!---
+{
+    "titles": [
+        "latedef"
+    ],
+    "slugs": [
+        "option-jshint-latedef"
+    ],
+    "linters": [
+        "jshint"
+    ],
+    "author": "jallardice",
+    "subject": "option"
+}
+-->
+
+### What does this option do?
+
+The JSHint `latedef` option is used to ensure variables and functions are
+declared before they are used. That is to say, the declarations appear
+physically in the source code above references to those declared variables or
+functions. Because declarations in JavaScript are hoisted to the top of the
+scope in which they occur it is perfectly safe to reference them earlier.
+
+In the following example the `doStuff` function declaration is hoisted to the
+top of the global scope so it is accessible throughout the program regardless of
+its position in the source:
+
+<!---
+{
+    "linter": "jshint"
+}
+-->
+```javascript
+/*jshint latedef: true */
+doStuff();
+function doStuff() {}
+```
+
+### When should I use this option?
+
+The use of the `latedef` JSHint option will cause a "['{a}' was used before it
+was defined][latedef]" error any time it encounters a reference to an identifier
+that has not yet been declared. By declaring variables and functions before you
+need to refer to them you can make your code easier to read through, since most
+people will read it from top to bottom. If a function is declared at the bottom
+of a file but used throughout the reader will have to scroll around to find the
+definition rather than immediately seeing it at the top.
+
+<!---
+{
+    "linter": "jshint"
+}
+-->
+```javascript
+/*jshint immed: true */
+function doStuff() {}
+doStuff();
+```
+
+Note that this is an *enforcing* option which means JSHint does not apply it by
+default. If you do not explicitly set this option to `true` JSHint will allow
+references to appear before declarations.
+
+#### Recommendation
+
+Set this option to `true` (ensures declarations appear before references).
+
+[latedef]: /a-was-used-before-it-was-defined