When would you use a do while loop?

The do/while loop is a variant of the while loop. This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true.

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    Syntax

    do {
      // code block to be executed
    }
    while (condition);

    The example below uses a do/while loop. The loop will always be executed at least once, even if the condition is false, because the code block is executed before the condition is tested:

    The do...while statement creates a loop that executes a specified statement until the test condition evaluates to false. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.

    do
      statement
    while (condition)
    

    statement

    A statement that is executed at least once and is re-executed each time the condition evaluates to true. To execute multiple statements within the loop, use a block statement ({ /* ... */ }) to group those statements.

    condition

    An expression evaluated after each pass through the loop. If condition evaluates to true, the statement is re-executed. When condition evaluates to false, control passes to the statement following the do...while.

    Note: Use the

    let result = "";
    let i = 0;
    do {
      i += 1;
      result += `${i} `;
    } while (i > 0 && i < 5);
    // Despite i === 0 this will still loop as it starts off without the test
    
    console.log(result);
    
    0 statement to stop a loop before condition evaluates to false.

    In the following example, the do...while loop iterates at least once and reiterates until

    let result = "";
    let i = 0;
    do {
      i += 1;
      result += `${i} `;
    } while (i > 0 && i < 5);
    // Despite i === 0 this will still loop as it starts off without the test
    
    console.log(result);
    
    4 is no longer less than 5.

    let result = "";
    let i = 0;
    do {
      i += 1;
      result += `${i} `;
    } while (i > 0 && i < 5);
    // Despite i === 0 this will still loop as it starts off without the test
    
    console.log(result);
    

    In some cases, it can make sense to use an assignment as a condition — but when you do, there's a right way to do it, and a wrong way; the

    let result = "";
    let i = 0;
    do {
      i += 1;
      result += `${i} `;
    } while (i > 0 && i < 5);
    // Despite i === 0 this will still loop as it starts off without the test
    
    console.log(result);
    
    5 documentation has a section with an example showing a general best-practice syntax you should know about and follow.