روش Extract Variable برای خوانایی کد

1// Without extract-variable
2function f() {
3  if (
4    platform.toUpperCase().indexOf("MAC") > -1 &&
5    browser.toUpperCase().indexOf("IE") > -1 &&
6    resize > 0
7  ) {
8    // do something
9  }
10}

1// With extract-variable
2function f() {
3  const isMacOs = platform.toUpperCase().indexOf("MAC") > -1;
4  const isIE = browser.toUpperCase().indexOf("IE") > -1;
5  const wasResized = resize > 0;
6  
7  if (isMacOs && isIE && wasResized) {
8    // do something
9  }
10}

1// Without extract-variable
2function g(orders) {
3  for (let i = 0; i < orders.length; i++) {
4    // do something
5  }
6}

1// With extract-variable
2function g(orders) {
3  const len = orders.length;
4  
5  for (let i = 0; i < len; i++) {
6    // do something
7  }
8}