Drupal.t() placeholder replacement is wonky.

A) Because Drupal.t() loops through the placeholders in the order they are defined, placeholders that start with identical strings, for example "!price" and "!price_formatted", can cause problems.

Example

var params = {
  "!foo": "foo",
  "!bar": "bar",
  "!foobar": "banana"
}
alert(Drupal.t('!foobar', params));

the expected output is 'banana', the actual output is 'foobar' (the value of !foo + the remaining literal 'bar').

Solution

One solution could be sorting the args by descending key first, making the longer strings occur before their shorter versions so they're replaced first.

B) By default, javascript's string.replace only replaces the first occurrence of a string.

Example

var params = {
  "!foo": "foo",
  "!bar": "bar",
  "!foobar": "banana"
}
alert(Drupal.t('!foobar !foobar !foobar', params));

Expected result: "banana banana banana"
Actual result: "foobar banana !foobar"

edit: changed an error in the second example.