Commit ddea8395 authored by Rene Saarsoo's avatar Rene Saarsoo
Browse files

Hack EsprimaJS to retrieve AST line numbers faster. 

Created a fork of EsprimaJS which adds line number as 3rd item to
"range" array.  This way we can skip the "loc" option, which caused
a huge performance penalty. Now we're back to normal.

Parsing times for sencha touch source:

Initially:           4.5s
After adding loc:    7.9s
With hacked esprima: 4.6s

The fork is located at:

  https://github.com/nene/esprima/tree/linenr-in-range
parent ef81c54e

lib/jsduck/ast.rb

+4 −1
Original line number Diff line number Diff line
@@ -252,7 +252,10 @@ module JsDuck 
        else

          cfg[:inheritdoc] = {}

          cfg[:autodetected] = true

          cfg[:linenr] = p["loc"]["start"]["line"]

          # Get line number from third place at range array.

          # This third item exists in forked EsprimaJS at

          # https://github.com/nene/esprima/tree/linenr-in-range

          cfg[:linenr] = p["range"][2]

          configs << cfg

        end

      end

lib/jsduck/esprima.rb

+1 −1
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ module JsDuck 
    # Returns the resulting AST

    def parse(input)

      @v8['js'] = input

      json = @v8.eval("JSON.stringify(esprima.parse(js, {comment: true, range: true, loc: true, raw: true}))")

      json = @v8.eval("JSON.stringify(esprima.parse(js, {comment: true, range: true, raw: true}))")

      return JSON.parse(json, :max_nesting => false)

    end