alguidelines/content/docs/BestPractices/string-value-tokens/index.md

title	tags	categories
String Values in Tokens	AL Readability Maintainability	Best Practice

Created by Microsoft, Described by Peter Conijn

Description

In some cases, notably when storing or retrieving values in key/value objects like dictionaries, XML or JSON objects, you will require a key value. In order to keep these tags maintainable, these key values should never be hard-coded, but should be stored in locked labels. Such locked labels should - as per convention - have the suffix -Tok.

Example 1

In this example, we show the wrong and right way to store values into a JSON object. These examples or course also applies to other key/value types. Do note that in these examples, as per JSON guidlines, the keys are in camelCase rather than PascalCase.

Bad code

    local procedure AddValuesToJson(Customer: Record Customer) JObject: JsonObject
    begin
        JObject.Add('customerName', Customer.Name);
        JObject.Add('customerAddress', Customer.Address);
    end;

Good code

    var
        NameKeyTok: Label 'customerName', Locked = true;
        AddressKeyTok: Label 'customerAddress', Locked = true;

    local procedure AddValuesToJson(Customer: Record Customer) JObject: JsonObject
    begin
        JObject.Add(NameKeyTok, Customer.Name);
        JObject.Add(AddressKeyTok, Customer.Address);        
    end;

Example 2

Bad code

    local procedure ParseJsonObject(JObject: JsonObject)
    var
        Customer: Record Customer;
    begin
        Customer.Init();
        Customer.Name := GetJsonValueAsText(JObject, 'customerName');
        Customer.Address := GetJsonValueAsText(JObject, 'customerAddress');
        // ...More code...
    end;

Good code

    var
        NameKeyTok: Label 'customerName', Locked = true;
        AddressKeyTok: Label 'customerAddress', Locked = true;

    local procedure ParseJsonObject(JObject: JsonObject)
    var
        Customer: Record Customer;
    begin
        Customer.Init();
        Customer.Name := GetJsonValueAsText(JObject, NameKeyTok);
        Customer.Address := GetJsonValueAsText(JObject, AddressKeyTok);
        // ...More code...
    end;