A parser for SVG's path syntax


An SVG path parser, originally built from the PEG.js grammar specified here, published as an NPM module.

Grammar originally written by Gavin Kistner.

Takes an SVG path string. The following code…

var parse = require('svg-path-parser');
var d='M3,7 5-6 L1,7 1e2-.4 m-10,10 l10,0  \
  V27 89 H23           v10 h10             \
  C33,43 38,47 43,47   c0,5 5,10 10,10     \
  S63,67 63,67         s-10,10 10,10       \
  Q50,50 73,57         q20,-5 0,-10        \
  T70,40               t0,-15              \
  A5,5 45 1,0 40,20    a5,5 20 0,1 -10-10  Z';

…will yield an array of commands that define the path, like so:

  { code:'M', command:'moveto', x:3, y:7 },
  { code:'L', command:'lineto', x:5, y:-6 },
  { code:'L', command:'lineto', x:1, y:7 },
  { code:'L', command:'lineto', x:100, y:-0.4 },
  { code:'m', command:'moveto', relative:true, x:-10, y:10 },
  { code:'l', command:'lineto', relative:true, x:10, y:0 },
  { code:'V', command:'vertical lineto', y:27 },
  { code:'V', command:'vertical lineto', y:89 },
  { code:'H', command:'horizontal lineto', x:23 },
  { code:'v', command:'vertical lineto', relative:true, y:10 },
  { code:'h', command:'horizontal lineto', relative:true, x:10 },
  { code:'C', command:'curveto', x1:33, y1:43, x2:38, y2:47, x:43, y:47 },
  { code:'c', command:'curveto', relative:true, x1:0, y1:5, x2:5, y2:10, x:10, y:10 },
  { code:'S', command:'smooth curveto', x2:63, y2:67, x:63, y:67 },
  { code:'s', command:'smooth curveto', relative:true, x2:-10, y2:10, x:10, y:10 },
  { code:'Q', command:'quadratic curveto', x1:50, y1:50, x:73, y:57 },
  { code:'q', command:'quadratic curveto', relative:true, x1:20, y1:-5, x:0, y:-10 },
  { code:'T', command:'smooth quadratic curveto', x:70, y:40 },
  { code:'t', command:'smooth quadratic curveto', relative:true, x:0, y:-15 },
  { code:'A', command:'elliptical arc', rx:5, ry:5, xAxisRotation:45, largeArc:true, sweep:false, x:40, y:20 },
  { code:'a', command:'elliptical arc', relative:true, rx:5, ry:5, xAxisRotation:20, largeArc:false, sweep:true, x:-10, y:-10 },
  { code:'Z', command:'closepath' }
  • Fix bug that prevented more than two subpaths from being returned.
  • Changed return values to represent each unique path command as its own object, regardless of whether the markup merged them or not. Arguments for a command (e.g. .x) are no longer in a .args array of values, but are instead part of the command object itself.
  • Unroll recursive grammar descriptions that could cause parsing a large path to overflow the stack.
  • Fix bug that prevented parsing some valid documents.
  • Fix parsing of numbers other than integers to work.
  • First moveto command is always absolute.
  • Additional coordinates after moveto are treated as lineto.