js2coffee/lib/transforms/exponents.coffee

JavaScript to CoffeeScript compiler

{ replace } = require('../helpers')
TransformerBase = require('./base')

###
# Transforms `Math.pow(2,8)` into `2 ** 8`
###

module.exports = class extends TransformerBase

  CallExpression: (node) ->
    isExponent =
      node.callee?.type is 'MemberExpression' and
      node.callee?.object?.type is 'Identifier' and
      node.callee?.object?.name is 'Math' and
      node.callee?.property?.type is 'Identifier' and
      node.callee?.property?.name is 'pow' and
      node.arguments?.length is 2

    return node unless isExponent

    replace node,
      type: 'BinaryExpression'
      left: node.arguments[0]
      operator: '**'
      right: node.arguments[1]