Дмитрий Беляев

for(var i = 0; i < 3; i++) {
  let j = i; // доступна только на этой итерации в этом блоке
  setTimeout(() => console.log(j), 0);
}
/*
0
1
2
*/

interface Package {
  id: number;
  activated: boolean;
  name: string;
}

interface ActivatedPackage extends Package {
  activated: true;
}

interface OptionalProps {
  foo: string;
  bar: number
}

const activatedPackages: Array<ActivatedPackage & Partial<OptionalProps>> = [ ... ];

const handleChange = (event: React.FormEvent<HTMLFormElement>) => {
  console.log(event.currentTarget.name)
}

function partial( f, ...a ) {
  return function( ...b ) { return f.call( this, ...a, ...b ) }
}

function sumNumbers(maxNumber) {
    const buf = new Int8Array(maxNumber);
    let answer = maxNumber > 2 ? 2 : 0;
    for(let i = 3; i < maxNumber; i += 2) {
        if (buf[i] === 1) {
            continue;
        }
        answer += i;
        const i2 = i * 2;
        for(let j = i * i; j < maxNumber; j += i2) {
            buf[j] = 1;
        }
    }
    
    return answer;
}

var array = [
  {
    'key1': 'value1'
  },
  {
    'key2': 'value2'
  },
  {'key1': 'value1-b'},
  {'key1': 'value1-c'},
]

const getValues = (array, key) => array.filter((item) => item.hasOwnProperty(key))
  .map((item) => item[key]);

getValues(array, "key1") // [ "value1", "value1-b", "value1-c" ]

fs.writeFile(file, data[, options], callback)#
History:

• file <string> | <Buffer> | <URL> | <integer> filename or file descriptor
  
• data

  <string> | <Buffer> | <TypedArray> | <DataView> | <Object>

  
  
• options <Object> | <string>
  • encoding <string> | <null> Default: 'utf8'
    
  • mode <integer> Default: 0o666
    
  • flag <string> See support of file system flags. Default: 'w'.
    
  • signal <AbortSignal> allows aborting an in-progress writeFile
    
  
  
• callback <Function>
  • err <Error> | <AggregateError>
    
  
  
  

When file is a filename, asynchronously writes data to the file, replacing the file if it already exists. data can be a string or a buffer.

When file is a file descriptor, the behavior is similar to calling fs.write() directly (which is recommended). See the notes below on using a file descriptor.

The encoding option is ignored if data is a buffer.

If data is a plain object, it must have an own (not inherited) toString function property.
...