Infinite loop in Safari

[mlenderink]

Got an infinite loop while using pow
Seems related to MikeMcl/bignumber.js#120

[MikeMcl]

Okay, thanks for the report. I'll take a look this weekend.

What version of iOS?
I think iOS 10.3.2 is the latest - is the bug still present there?

[mlenderink]

I had this issue on Safari 10.1 on my mac using macOS 10.12.4

[MikeMcl]

Apologies for the delay.

Is the following true or false on the afflicted Safari?

Object.keys({ '250': 0.5, '1000': 0.1 }).length === 2

[mlenderink]

false

[MikeMcl]

Thanks, Martin.

Please could you also tell me if running the following code fixes this issue

if (Object.keys({'250': 0.5, '1000': 0.1}).length !== 2) {
  Array.prototype.unshift = function () {
    Array.prototype.splice.apply(this, Array.prototype.concat.apply([0, 0], arguments));
    return this.length;
  };
  Array.prototype.shift = function () {
    return Array.prototype.splice.call(this, 0, 1)[0];
  };
}

[taylor-cedar]

@MikeMcl That code works, but I don't think it's a good idea to change the Array prototype in a library. Other libraries may be depending upon other behavior. A better method is something like this.

var shift, unshift;
if (Object.keys({'250': 0.5, '1000': 0.1}).length == 2) {
  unshift = Function.prototype.call.bind(Array.prototype.unshift)
  shift = Function.prototype.call.bind(Array.prototype.shift)
} else {
  unshift = function(arr, /*new array elements */) {
    Array.prototype.splice.apply(arr, Array.prototype.concat.apply([0, 0], Array.prototype.slice.call(arguments, 1));
    return arr.length
  }
  shift = function (arr) {
    return Array.prototype.splice.call(arr, 0, 1)[0];
  };
}

And then you can use the shift and unshift methods without affecting the prototype.

shift(myArr)

unshift(myArr, 3)

[MikeMcl]

@taylor-cedar

Thanks for testing the code and for offering another possible solution.

My preference would be to not have to make changes to my libraries to work around bugs elsewhere.

Changing the prototype seems reasonable to me here because if the bug is present then the built-in shift and unshift implementations stop arrays working reliably, not just in this library but everywhere.

For example, if the bug is present

var arr = [0, 2147483648];
arr.shift(); 
arr[1] = 1;
// arr should be [2147483648, 1] but is [2147483648] in Safari

[taylor-cedar]

I understand, but think about if every library owner has the same idea. Most code bases use 50-100 libraries. If every library overrides the Array prototype, it will be very inefficient and very unpredictable.

[benfletcher]

FWIW, Safari 11.0 on Mac doesn't have this issue. It may also be fixed on 10.x updates. 11 is due for imminent release with new High Sierra update.

[MikeMcl]

@numbergames

Thanks for the info.

[Xotic750]

I was having a look to see if this could be globally fixed with JavaScript

es-shims/es5-shim#449

I didn't find a global fix, but I did come up with something that may be useful, though I can't test it as I don't have access to Safari.

https://github.com/Xotic750/create-array-fix-x

Link to tests

https://rawgit.com/Xotic750/create-array-fix-x/master/tests/index.html