expected block end in if statement when using static values' methods and attributes

[Javascipt]

When using a static value I can't use its methods. example :

   {% if 'abcdef'.indexOf('abc') === 0 %}

it's always expecting the end block token

Other examples that throws the same exception is this

   {% if (str1 or str2).indexOf('abc') === 0 %}

or

   {% if [1, 2, 3].indexOf(1) === 0 %}

[flaviolivolsi]

+1