node.js - RangeError: Maximum call stack size exceeded (Babel Ramda) -

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this code produces stack trace below it:

import r 'ramda';  function quicksort(list) {   if ( r.isempty(list) ) return list;   let pivot = r.head(list);   let lesser  = r.filter( e => e < pivot , list );   let greater = r.filter( e => e >= pivot, list );   return r.concat( quicksort(lesser), pivot, quicksort(greater) );  }  var sorted = quicksort([2,3,1]); console.log(sorted);

stack trace:

$ babel-node quicksort2015.js /users/ivan/.nvm/versions/node/v4.1.2/lib/node_modules/babel/node_modules/babel-core/node_modules/core-js/modules/es6.object.to-string.js:3 var classof = require('./$.classof')                     ^ rangeerror: maximum call stack size exceeded @ array.tostring (native) @ module.exports      (/users/ivan/.nvm/versions/node/v4.1.2/lib/node_modules/babel/node_modules/babel-core/node_modules/core-js/modules/$.cof.js:4:19) @ module.exports      (/users/ivan/.nvm/versions/node/v4.1.2/lib/node_modules/babel/node_modules/babel-core/node_modules/core-js/modules/$.classof.js:13:13) @ array.tostring (/users/ivan/.nvm/versions/node/v4.1.2/lib/node_modules/babel/node_modules/babel-core/node_modules/core-js/modules/es6.object.to-string.js:8:25) @ type (/users/ivan/dev/quicksort/node_modules/ramda/dist/ramda.js:3345:100) @ f1 (/users/ivan/dev/quicksort/node_modules/ramda/dist/ramda.js:166:27) @ _equals (/users/ivan/dev/quicksort/node_modules/ramda/dist/ramda.js:4038:13) @ equals (/users/ivan/dev/quicksort/node_modules/ramda/dist/ramda.js:4664:16) @ f2 (/users/ivan/dev/quicksort/node_modules/ramda/dist/ramda.js:201:24) @ object.isempty (/users/ivan/dev/quicksort/node_modules/ramda/dist/ramda.js:5220:29)

i though babel handle tail call optimization? in case, it's such short list, should not deep, right?

this due filtering entire list, rather tail of list lesser , greater.

e.g. try following:

function quicksort(list) {   if (list.length <= 1) return list;   var x = r.head(list);   var xs = r.tail(list);   var lesser  = r.filter(r.lt(r.__, x), xs);   var greater = r.filter(r.gte(r.__, x), xs);   return r.concat(quicksort(lesser), r.prepend(x, quicksort(greater))); }

unfortunately doesn't benefit tail-call optimisation either, recursive calls quicksort not in tail-call position.


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