bd-short-message-platform/app/middleware/utils/getString.js

// 截取数组元素，拼接成字符串并返回
module.exports = (arr, start, end) => {
    let newString = '';
    arr.forEach((element, index) => {
        if (index >= start && index <= end) {
            newString = newString + element;
        }
    });
    return newString;
};