Show HN: Virtual pet game made for my daughter

Re:Show HN: Virtual pet game made for my daughter by nkrisc on Thursday November 21, 2019 @12:12PM (#21596470)

I've never seen this pattern before in JS, in the parameters for the constructor. playing with it in the browser, I can see it lets you define default values for expected arguments when calling it but you can provide other values.

What is this called? I'd like to read more about it.

  class Resource{
    constructor({
      min = 0,
      max = 1,
      count = 0
    }={}){
      this.min = min;
      this.max = max;
      this.count = count;
    }
  }

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Re:Show HN: Virtual pet game made for my daughter by lxe on Thursday November 21, 2019 @04:36PM (#21599938)

Destructuring parameters with default values.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

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Re:Show HN: Virtual pet game made for my daughter by orisa2 on Thursday November 21, 2019 @12:21PM (#21596610)

From the post, I wasn't sure if you knew, but JS also has regular default parameters if that's all you want.

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Re:Show HN: Virtual pet game made for my daughter by capableweb on Thursday November 21, 2019 @01:26PM (#21597519)

Not as nice though, as the arguments still depend on the order. Passing a object gives the benefit of named arguments AND position of the arguments no longer matter (as object keys don't have order and also, it's a object with key/values)

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Re:Show HN: Virtual pet game made for my daughter by chiyc on Thursday November 21, 2019 @12:16PM (#21596535)

I think I would call it nested destructuring with default values.

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Re:Show HN: Virtual pet game made for my daughter by nkrisc on Thursday November 21, 2019 @12:18PM (#21596557)

Destructuring, that rings a bell. Thank you.

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Re:Show HN: Virtual pet game made for my daughter by capableweb on Thursday November 21, 2019 @01:25PM (#21597494)

Yeah, the trick is basically many things chained together. First is to pass a object to a function instead of position-locked arguments. Second is to default to a empty object. Third is to destruct the object in the function parameter directly. Fourth to supply default destruct values. Fifth is to set the values in the current instance of that class.

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