PHP7.4 上月 28 号已宣布了。又带来了一些新特征。可以让我们的代码写的更少了

<?php

class User {

  public int $age;

  public string $name

} 

$user = new User();

$user->age = 10;

$user->name = "张三";

//error

$user->age = "zhang";//需求传递int

<?php

$factor = 10;

$nums = array_map(fn($n)=>$n * $factor,[1,2,3]);//[10,20,30]

//之前的写法

$nums = array_map(function($num)use($factor){

  return $num * $factor;

},[1,2,3])

<?php

class A {}

class B extends A {}

class Producer {

    public function method(): A {}

}

class ChildProducer extends Producer {

    public function method(): B {}

}

?>

<?php

$parts = ['apple', 'pear'];

$fruits = ['banana', 'orange', ...$parts, 'watermelon'];//['banana', 'orange', 'apple', 'pear', 'watermelon'];

//老的写法

$fruits = array_merge(['banana', 'orange'],$parts,['watermelon']);

<?php

$array['key'] ??= computeDefault();

// 老的写法

if (!isset($array['key'])) {

    $array['key'] = computeDefault();

}

?>

<?php

6.674_083e-11; // float

299_792_458;   // decimal

0xCAFE_F00D;   // hexadecimal

0b0101_1111;   // binary

?>