code: function ( qu, value ) {
  		if ( sys.isArray( value ) ) {
  			return sys.find( value, function ( entry ) {
  				return JSON.stringify( qu.operands[0] ) === JSON.stringify( entry );
  			} ) !== void 0;
  		} else {
  			return JSON.stringify( qu.operands[0] ) === JSON.stringify( value );
  		}
  	}
docs: `$eq` performs a `===` comparison by comparing the value directly if it is an atomic value.
  otherwise if it is an array, it checks to see if the value looked for is in the array.
  `{field: value}` or `{field: {$eq : value}}` or `{array: value}` or `{array: {$eq : value}}`
  @name $eq
  @memberOf module:documents/probe.queryOperators
  @example
  var probe = require("documents/probe");
  probe.find( data, {categories : "cat1"} );
  // is the same as
  probe.find( data, {categories : {$eq: "cat1"}} );