问循环遍历字符串数组，每次循环之间有任意时间间隔(JS)

EN

{ // A scoping block so the variables aren't globals
  // (unnecessary if you're using modules)
    let stringArray = ['TestOne', 'TestTwo'];
    let arrayIndex = 0;
    let stringIndex = 1;
    // Start a timer that will call the callback every 250ms (or so)
    setInterval(() => {
        // Get the relevant string
        const str = stringArray[arrayIndex];
        // Output the substring
        console.log(str.substring(0, stringIndex));
        // Move to the next character
        ++stringIndex;
        // Need to move to next string?
        if (stringIndex > str.length) {
            // Yes, go back to the beginning of the string and
            // move to the next entry in the array, wrapping
            // around if we reach the end
            stringIndex = 1;
            arrayIndex = (arrayIndex + 1) % stringArray.length;
        }
    }, 250);
}

arrayIndex = (arrayIndex + 1) % stringArray.length;