[GFM] Table delimiter row requires more than one `-` in each cell.

Description

showdown.setOption('tables', true);
showdown.setOption('tablesHeaderId', true);

var converter = new showdown.Converter(),
text      = `|a|b|c|d|
|:-|:-:|:-:|-:|
|1|2|3|4|`,
						 html      = converter.makeHtml(text);
						$ ('[data]') .html (html)

Contributor guide

Tech stack

javascript

Domain

backenddocumentation

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

2

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

under 1 hour

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

None

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

30

Research direction

The issue is about the table delimiter row in GitHub Flavored Markdown. The current parser requires at least two dashes in each cell of the delimiter row, but GFM spec allows a single dash. Investigate the showdown table parsing logic, likely in `src/markdown/table.js` or `src/converter.js`. Check the regex that validates delimiter rows and modify it to accept one or more dashes. The issue has an assignee, so verify if work is already in progress.