Cannot gulp compile the repository: "throw e; "

[coderodde]

Hello,

When I attempt to invoke gulp compile, I get

$ gulp compile
[09:04:55] Using gulpfile ~/Documents/PathFinding.js/gulpfile.js
[09:04:55] Starting 'clean'...
[09:04:55] Finished 'clean' after 6.83 ms
[09:04:55] Starting 'browserify'...
/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:3872
            throw e;
            ^

Error: Line 1218: Invalid left-hand side in assignment
    at throwError (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:1161:21)
    at throwErrorTolerant (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:1172:24)
    at parseAssignmentExpression (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:1998:17)
    at /home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:3609:38
    at parseArguments (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:1579:27)
    at trackLeftHandSideExpressionAllowCall (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:3511:34)
    at parsePostfixExpression (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:1703:20)
    at /home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:3609:38
    at parseUnaryExpression (/home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:1737:20)
    at /home/rodde/Documents/PathFinding.js/node_modules/esrefactor/node_modules/esprima/esprima.js:3609:38

Any idea how to fix this?