Overview of JavaScript ES6 features

Re:Overview of JavaScript ES6 features by dsp1234 on Monday October 24, 2016 @02:13PM (#12781287)

  const x = Object.freeze({
    y: {
      foo: 'bar'
    }
  });
  x.y.foo = 'baz'
  console.log(x.y.foo) //baz

immutablejs might be overkill, but not having, and using, a recursive freeze is going to bite a lot of people if the advice is just 'const + Object.freeze'.

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Re:Overview of JavaScript ES6 features by BinaryIdiot on Monday October 24, 2016 @02:39PM (#12781547)

> immutablejs might be overkill, but not having, and using, a recursive freeze is going to bite a lot of people if the advice is just 'const + Object.freeze'.

No one should be trying to use a recursive freeze (if they are I would argue their data structure is poorly suited to be immutable).

I'm not saying `const` + `Object.freeze()` gets you Immutablejs I'm saying it gets you, likely, what you want / need.

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Re:Overview of JavaScript ES6 features by dsp1234 on Monday October 24, 2016 @04:05PM (#12782350)

Our team was just hit with this:

  const x = Object.freeze([
    {id: 1, value: 'foo'},
    {id: 2, value: 'bar'},
    {id: 3, value: 'baz'},
  ])

  ...

  //Bug in the code
  x[0].value = 'test'

First comment on the bug report was:

'This shouldn't be possible as the array is const and frozen'.

their data structure is poorly suited to be immutable

An array of object seems completely reasonable. Even an array of objects, where those objects themselves have keys which are objects/arrays doesn't seem unreasonable.

We'll just have to agree to disagree.

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Re:Overview of JavaScript ES6 features by BinaryIdiot on Monday October 24, 2016 @05:25PM (#12783068)

> First comment on the bug report was: > 'This shouldn't be possible as the array is const and frozen'.

Yeah const and Object.freeze() are not exactly the most intuitive depending on your level of JavaScript internals knowledge (and even then I don't think const is very intuitive but I digress).

> We'll just have to agree to disagree.

Fair enough! I would just caution trying to make complex objects immutable; it can be handy if you're developing a library and don't trust the dev on the other side (to a degree, copying may be preferable depending on the context) but it can complicate things and lead to some performance and development pattern issues.

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