index.js
function assertLayout(value, defaultLayout) {
  var isFalsey = require('falsey');
  if (value === false || (value && isFalsey(value))) {
    return null;
  } else if (!value || value === true) {
    return defaultLayout || null;
  } else {
    return value;
  }
}
function assertLayout(value, defaultLayout) {
  var isFalsey = require('falsey');
  if (value === false || (value && isFalsey(value))) {
    return null;
  } else if (!value || value === true) {
    return defaultLayout || null;
  } else {
    return value;
  }
}
function assertLayout ( value , defaultLayout ) { var isFalsey = require ( 'falsey' ) ; if ( value === false || ( value && isFalsey ( value ) ) ) { return null ; } else if ( ! value || value === true ) { return defaultLayout || null ; } else { return value ; } }
Assert whether or not a layout should be used based on
the given `value`. If a layout should be used, the name of the
layout is returned, if not `null` is returned.

@param  {*} `value`
@return {String|Null} Returns `true` or `null`.
@api private
Assert whether or not a layout should be used based on the given value . If a layout should be used the name of the layout is returned if not null is returned .