javascript - What do square brackets around a property name in an object literal mean? -

i've been writing in js while , have not used form:

  dist: {     files: {       [bpr + 'lib/monster.min.js']: ['<%= concat.dist.dest %>']     }   } }

the

[]:[]

it works, have not used or seen before.

only es6. called "computed property names"

from mdn:

starting ecmascript 2015, object initializer syntax supports computed property names. allows put expression in brackets [], computed property name.

Two