Enumerations

Enumerations eliminate a lot of UI code duplication while enabling accurate translations. <fbt:enum> and fbt::enum both provide the ability to add your ad-hoc enumerations.

Adhoc enums

Adhoc enums can be provided inline to the enum-range attribute or as the second parameter to fbt::enum.

Enum map

<fbt desc="buy prompt">
  Buy a new
  <fbt:enum enum-range="{{ json_encode([
    'CAR' => 'car',
    'HOUSE' => 'house',
    'BOAT' => 'boat',
    'HOUSEBOAT' => 'houseboat',
  ]) }}" value="{{ $enumVal }}" />!
</fbt>

fbt(
  'Buy a new ' .
    fbt::enum($enumVal, [
      'CAR' => 'car',
      'HOUSE' => 'house',
      'BOAT' => 'boat',
      'HOUSEBOAT' => 'houseboat',
    ]),
  'buy prompt',
);

Shorthand array (keys = values)

The shorthand array adhoc enum functions as though you had a [value => value] map.

<fbt desc="buy prompt">
  Buy a new
  <fbt:enum enum-range="{{ json_encode([
    'car', 'house', 'boat', 'houseboat'
  ]) }}" value="{{ $enumVal }}" />!
</fbt>

fbt(
  'Buy a new ' . fbt::enum($enumVal, ['car', 'house', 'boat', 'houseboat']) . '!',
  'buy prompt',
);

All the above examples extract the same 4 separate strings for translation in JSON like:

{
  "phrases": [
    {
      "hashToLeaf": {
        "tGN0j5ePJCeH9fIlp3Yq6w==": {"text": "Buy a new car!", "desc": "buy prompt"},
        "ElXst6oKNLh1XU8GjJucQQ==": {"text": "Buy a new house!", "desc": "buy prompt"},
        "fAHV109uPI7aCxZqNmuTfg==": {"text": "Buy a new boat!", "desc": "buy prompt"},
        "end24pKDi2/oxKff1YEXzQ==": {"text": "Buy a new houseboat!", "desc": "buy prompt"}
      },
      "project": "website app",
      "jsfbt": {
        "t": {
          "car": {"desc": "buy prompt", "text": "Buy a new car!"},
          "house": {"desc": "buy prompt", "text": "Buy a new house!"},
          "boat": {"desc": "buy prompt", "text": "Buy a new boat!"},
          "houseboat": {"desc": "buy prompt", "text": "Buy a new houseboat!"}
        },
        "m": [null]
      }
    }
  ]
}

Reusing the same enum value

When multiple enums depend on the same value, give them the same key, so that only the consistent combinations of their values are generated for translation:

<fbt desc="buy prompt">
  Buy a new <fbt:enum enum-range="<?=json_encode($range1)?>" value="<?=$value?>" key="item" />
  or a used <fbt:enum enum-range="<?=json_encode($range2)?>" value="<?=$value?>" key="item" />!
</fbt>

fbt(
  'Buy a new ' . fbt::enum($value, $range1, ['key' => 'item']) .
  ' or a used ' . fbt::enum($value, $range2, ['key' => 'item']) . '!',
  'buy prompt'
);

Facebook's fbt detects that the same variable is used. In PHP, the source code of values isn't available, so the key option has to be used instead.