在特定索引处插入字符串

问题描述：

如何在另一个字符串的特定索引处插入字符串？

How can I insert a string at a specific index of another string?

 var txt1 = "foo baz"

假设我想在foo之后插入bar我该如何实现？

Suppose I want to insert "bar " after the "foo" how can I achieve that?

我想到了 substring（），但必须有一个更简单更简单的方法。

I thought of substring(), but there must be a simpler more straight forward way.

答

您可以将自己的 splice（）原型化为String。

You could prototype your own splice() into String.

if (!String.prototype.splice) {
    /**
     * {JSDoc}
     *
     * The splice() method changes the content of a string by removing a range of
     * characters and/or adding new characters.
     *
     * @this {String}
     * @param {number} start Index at which to start changing the string.
     * @param {number} delCount An integer indicating the number of old chars to remove.
     * @param {string} newSubStr The String that is spliced in.
     * @return {string} A new string with the spliced substring.
     */
    String.prototype.splice = function(start, delCount, newSubStr) {
        return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
    };
}

示例

Example

String.prototype.splice = function(idx, rem, str) {
    return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));
};

var result = "foo baz".splice(4, 0, "bar ");

document.body.innerHTML = result; // "foo bar baz"

编辑：修改它以确保 rem 是绝对值。

Modified it to ensure that rem is an absolute value.

在特定索引处插入字符串

示例

Example

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