RegEx for Consecutive Expressions with OR?-CodePudding

How can i match a series of expressions with OR's? This is for scrubbing plain text data which may contain imbedded spaces or tabs at the front of each row. This is in preparation for a .split at newlines.

const oldStr = `abc
   abc
    abc`;

I want to replace:

newline   0 or more spaces OR tabs

with

newline

This achieves what i want

newStr = oldStr.replaceAll(/\n */g, "\n");  // newline   spaces
newStr = newStr.replaceAll(/\n\t*/g, "\n");  // newline   tabs

How to do that in a single statement? The following fail:

Attempt, with pipe:

newStr = oldStr.replaceAll(/\n *|\t*/g, "\n");

Attempt, with parens around the OR:

newStr = oldStr.replaceAll(/\n( *|\t*)/g, "\n");

Attempt, with slashes around the OR:

newStr = oldStr.replaceAll(/\n/ *|\t*/g, "\n");

Attempt, with square brackets instead of pipe:

newStr = oldStr.replaceAll(/\n[ *\t*]/g, "\n");

Attempt, with quotes and pipe:

newStr = oldStr.replaceAll("\n *\t|*/g", "\n");

Attempt, with quotes and pipe and parens:

newStr = oldStr.replaceAll("\n( *|\t*)/g, "\n");

Attempt, with quotes and square brackets:

newStr = oldStr.replaceAll("\n[ *\t*]/g", "\n");

Feel free to offer a solution which combines the cleaning with a .split statement, or a non-regex solution.

CodePudding user response：

You don't need to "prepare" for splitting, just split by \n, optionally surrounded by spaces:

text = `   How razorback-jumping 
   frogs 
can
 \t   level six \t
         \t piqued gymnasts!`         
         
console.log(text.trim().split(/[ \t]*\n[ \t]*/g))

CodePudding user response：

The square brackets should work, but the * (or ) modifier must be on the outside of it:

newStr = oldStr.replaceAll(/\n[ \t] /g, "\n");

I chose because it means "1 or more occurrences", it makes no sense to replace if there are 0 occurrences.

Demo:

let text = `ABC
   DEF
   \t\tGHI
\t\tJKL
MNO`;
console.log(text.split("\n"));

text = text.replaceAll(/\n[ \t] /g, "\n");
console.log(text.split("\n"))