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Recommended Techniques

Use Searchable Prefixed Checking Function Names

Prefix checking function names that run before tested functions with 'PRE_check_', and prefix 'POST_check_' to checking routines that execute after tested functions. It is easy to see the relationships this way.

/**/  type_czech = TypeCzech('LOG-ERRORS')
/**/
/**/  function PRE_check_yourFunc(){ /* before check */ }
/**/  function POST_check_yourFunc(){ /* after check */ }
/**/
/**/  yourFunc = type_czech.linkUp(yourFunc, PRE_check_yourFunc, POST_check_yourFunc)

function yourFunc(){}

Or by using 'before_' and 'after_' so the error messages make sense.

/**/  type_czech = TypeCzech('LOG-ERRORS')
/**/
/**/  function before_yourFunc(){ /* before check */ }
/**/  function after_yourFunc(){ /* after check */ }
/**/
/**/  yourFunc = type_czech.linkUp(yourFunc, before_yourFunc, after_yourFunc)

function yourFunc(){}

Multiple Checked Issues

Return nothing if no error, and include actual parameters only when actually individually testing them as below.

/**/  type_czech = TypeCzech('LOG-ERRORS')
/**/
/**/  function PRE_check_yourFunc(first_name, last_name){
/**/    the_parameters = [first_name, last_name]
/**/    type_issue = type_czech.checkParam_type(the_parameters, ['string', 'string'])
/**/    if (type_issue) return type_issue
/**/
/**/    empty_issue = type_czech.checkParam_empty(the_parameters, ['EMPTY-ERROR', 'EMPTY-ERROR'])
/**/    if (empty_issue) return empty_issue
/**/
/**/    if (first_name.length===1) return 'Error, first_name is 1 character'
/**/  }
/**/
/**/  yourFunc = type_czech.linkUp(yourFunc, PRE_check_yourFunc)

function yourFunc(first_name, last_name){}

yourFunc('Mr', 'Early')

yourFunc('Mr', 99)     // fail - number not string
yourFunc('Mr', '')     // fail - empty last name
yourFunc('A', 'Short') // fail - first name is 1 char

Recommended Structure With Classes

Keep TypeCzech code sparate from ordinary files as these local examples do 204, 304, 404, 504, and 604.

Easy detaching of TypeCzech can be done as below, without loading any checking code in the browser. When the two javaScript files below are not loaded then check_linkUp_first_last_full() is not run and no functions are linked up to checking functions.

// <script src="../../TypeCzech.js"></script>
// <script src="./604-oloo-external-checks.js"></script>

/**/  if (typeof check_linkUp_first_last_full === 'function') 
/**/    check_linkUp_first_last_full()

Recommended Functional Structure

The file, addInt2Int_tc.js, containing the PRE and POST type checking functions for addInt2Int()

// addInt2Int_tc.js

if (typeof TypeCzech !== 'function') {
  linkUp_addInt2Int = () => {}
} else {
  linkUp_addInt2Int = () => {
    type_czech = TypeCzech('LOG-ERRORS')

    function PRE_addInt2Int(first_int, second_int) {
      return type_czech.checkParam_type([first_int, second_int], ['number', 'number'])
    }

    function POST_addInt2Int(sum_int) {
      return type_czech.checkParam_type(sum_int, 'number')
    }
      
    addInt2Int = type_czech.linkUp(addInt2Int, PRE_addInt2Int, POST_addInt2Int)
  }
}

The file, main.html, when type checking is ON

<script src="TypeCzech.js">// on </script>

          <script src="addInt2Int_tc.js"></script>

          <script>
            linkUp_addInt2Int()

            function addInt2Int (first_int, second_int){
              return first_int + second_int
            }

          </script>

The file, main.html, when type checking is OFF, no need to erase line

<script s r c="TypeCzech.js"></script>

          <script src="addInt2Int_tc.js"></script>

          <script>
            linkUp_addInt2Int()

            function addInt2Int (first_int, second_int){
              return first_int + second_int
            }

          </script>

© 2024 Steen Hansen