CODEWITHSUNDEEP
javascript
sent1nel
sent1nel

Reputation: 1770

JavaScript Increment Operator isn't working?

So for some reason, when I use the increment operator in this code, it doesn't work. I've verified my variables are numbers.. Not sure what's going on.

var fs = require('fs')
  , bt = require('buffertools')

var start = 0;

fs.readFile(process.argv[2], function(err, data) {
  console.log(data);
  while (bt.indexOf(data, '\n', start)) {
    var nl = bt.indexOf(data, '\n', start); // nl is 40
    console.log(start, nl); // 0, 40
    console.log(data.slice(start, nl)); // works great!

    start = nl++; // reset the offset past that last character..
    console.log(start, typeof start); // start == 40? the heck? 'number'
    process.exit(); // testing
    //console.log(nl, start); 40, 40
  }
});

EDIT ------

And the solution...

"use strict";

var fs = require('fs')
  , bt = require('buffertools');

fs.readFile(process.argv[2], function(err, data) {
  var offset = 0;

  while (true) {
    var nl = bt.indexOf(data, '\n', offset);
    if (nl === -1) break;
    console.log(data.slice(offset, nl));
    offset = ++nl;
  }

  console.log(data.slice(offset));
});

Thanks!

Upvotes: 0

Views: 134

Answers (1)

Benjamin Gruenbaum
Benjamin Gruenbaum

Reputation: 276266

You're looking for ++nl and not nl++ , num++ increments the number and returns the old value.

This is true in many other languages too by the way.

Since you're not changing nl later at all, you can write this as:

    start = nl + 1;

Which is clearer.

Upvotes: 4

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