while

20157

while

let n = 0;

while (n < 3) {
  n++;
}

console.log(n);
// Expected output: 3

while (condition)
  statement

condition

statement while

statement

{ /* ... */ }

break condition

n while

let n = 0;
let x = 0;

while (n < 3) {
  n++;
  x += n;
}

n n x x n

n = 1x = 1
n = 2x = 3
n = 3x = 6

n < 3

const iterator = document.createNodeIterator(document, NodeFilter.SHOW_COMMENT);
let currentNode;
while (currentNode = iterator.nextNode()) {
  console.log(currentNode.textContent.trim());
}

while (currentNode = iterator.nextNode()) {

iterator.nextNode() currentNode
currentNode = iterator.nextNode()
console.log()

iterator.nextNode() null
currentNode = iterator.nextNode() null

=== = = ===

ESLint no-cond-assign

Expected a conditional expression and instead saw an assignment.

const iterator = document.createNodeIterator(document, NodeFilter.SHOW_COMMENT);
let currentNode;
while ((currentNode = iterator.nextNode())) {
  console.log(currentNode.textContent.trim());
}

ESLint no-cond-assign Prettier

while ((currentNode = iterator.nextNode()) !== null) {

while ((currentNode = iterator.nextNode()) && currentNode) {

while

const iterator = document.createNodeIterator(document, NodeFilter.SHOW_COMMENT);
for (
  let currentNode = iterator.nextNode();
  currentNode;
  currentNode = iterator.nextNode()
) {
  console.log(currentNode.textContent.trim());
}


ECMAScript 2027 LanguageSpecification # sec-while-statement

MDN

2025716 MDN

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