javascript - 如何使用 Javascript 在字符串中的每个新行之前/之后插入或删除制表符？

Question

考虑以下字符串，作为文本区域中的选择:

"I want to insert \n a tab after every newline in the this selection. \n I also want to know how to do the opposite, removing the tab before each newline in this selection."

以及所涉及代码的简化示例:

var userWantsToIndentSelection = true,
userWantsToOutdentSelection = false,
start = this.selectionStart,
end = this.selectionEnd,
selection = text.slice(start,end),
newline = /\r|\n/.exec(selection);

if(newline){
    if (userWantsToIndentSelection){

        // add tabs after each newline

    }
    else if (userWantsToOutdentSelection) {

        // remove tabs before each newline

    }
}

if(!newline){

    // Handling just one line (cursor at front of line, no selection) is simple.
    // Perhaps I don't need a special handler though
    // and can use the new line handler for single and multiple line selections.
    // Mention it in your answer if you like.

}

如何使用 Javascript 在字符串中的每个新行之前/之后插入或删除制表符？

Answer 1

你可以使用这个正则表达式src.replace(/^/gm, "\t");

^ 匹配行首

m 告诉正则表达式引擎使用多行模式，以便 ^ 将匹配每一行，而不仅仅是字符串的开头。