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feat: add checkMissingCells option to table-column-count #434

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e3e64b8
feat: add checkMissingCells option to table-column-count
TKDev7 Jun 21, 2025
a96d93d
change "will" to "might" in missingCells message
TKDev7 Jun 23, 2025
df056bb
Merge branch 'main' into checkMissingCells
TKDev7 Jun 27, 2025
c5d71b1
refactor types
TKDev7 Jun 27, 2025
95c4a54
rename message id and tweak docs
TKDev7 Jun 30, 2025
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19 changes: 18 additions & 1 deletion docs/rules/table-column-count.md
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Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ Examples of **correct** code for this rule:
<!-- Rows with fewer cells are valid because they render correctly and no data is lost -->
| Header | Header | Header |
| ------ | ------ | ------ |
| Cell | Cell | |
| Cell | Cell |
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Suggested change
| Cell | Cell |
| Cell | Cell | |

I think the original intention of this example is to show that an empty cell is okay. The following example already covers the change you made.

image

Could you revert the example?

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@TKDev7 TKDev7 Jun 30, 2025 •
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Its description says: <!-- Data row with fewer cells than header (VALID for this rule) -->. Without this change, the number of cells would have matched the header.


<!-- Table with some empty cells (VALID for this rule) -->
<!-- Missing cells are treated as empty and don't cause rendering issues -->
Expand All @@ -58,6 +58,23 @@ Examples of **correct** code for this rule:
| Single Cell |
```

## Options

The following options are available on this rule:

* `checkMissingCells: boolean` - When set to `true`, the rule will also flag rows that have fewer cells than the header row. (default: `false`)

Examples of **incorrect** code when configured as `"table-column-count": ["error", { checkMissingCells: true }]`:

```markdown
<!-- eslint markdown/table-column-count: ["error", { checkMissingCells: true }] -->

<!-- Data row with fewer cells than header -->
| Header | Header | Header |
| ------ | ------ | ------ |
| Cell | Cell |
```

## When Not To Use It

If you intentionally create Markdown tables where data rows are expected to contain more cells than the header, and you have a specific (perhaps non-standard) processing or rendering pipeline that handles this scenario correctly, you might choose to disable this rule. However, adhering to this rule is recommended for typical GFM rendering and data consistency.
Expand Down
52 changes: 46 additions & 6 deletions src/rules/table-column-count.js
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,10 @@
//-----------------------------------------------------------------------------

/**
* @typedef {import("../types.ts").MarkdownRuleDefinition<{ RuleOptions: []; }>} TableColumnCountRuleDefinition
* @import { MarkdownRuleDefinition } from "../types.js";
* @typedef {"extraCells" | "missingCells"} TableColumnCountMessageIds
* @typedef {[{ checkMissingCells?: boolean }]} TableColumnCountOptions
* @typedef {MarkdownRuleDefinition<{ RuleOptions: TableColumnCountOptions, MessageIds: TableColumnCountMessageIds }>} TableColumnCountRuleDefinition
*/

//-----------------------------------------------------------------------------
Expand All @@ -28,12 +31,30 @@ export default {
},

messages: {
inconsistentColumnCount:
extraCells:
"Table column count mismatch (Expected: {{expectedCells}}, Actual: {{actualCells}}), extra data starting here will be ignored.",
missingCells:
"Table column count mismatch (Expected: {{expectedCells}}, Actual: {{actualCells}}), row might be missing data.",
},

schema: [
{
type: "object",
properties: {
checkMissingCells: {
type: "boolean",
},
},
additionalProperties: false,
},
],

defaultOptions: [{ checkMissingCells: false }],
},

create(context) {
const [{ checkMissingCells }] = context.options;

return {
table(node) {
if (node.children.length < 1) {
Expand All @@ -46,20 +67,39 @@ export default {
for (let i = 1; i < node.children.length; i++) {
const currentRow = node.children[i];
const actualCellsLength = currentRow.children.length;
const lastActualCellNode =
currentRow.children[actualCellsLength - 1];

if (actualCellsLength > expectedCellsLength) {
const firstExtraCellNode =
currentRow.children[expectedCellsLength];

const lastActualCellNode =
currentRow.children[actualCellsLength - 1];

context.report({
loc: {
start: firstExtraCellNode.position.start,
end: lastActualCellNode.position.end,
},
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: {
actualCells: String(actualCellsLength),
expectedCells: String(expectedCellsLength),
},
});
} else if (
checkMissingCells &&
actualCellsLength < expectedCellsLength
) {
context.report({
loc: {
start: {
column:
lastActualCellNode.position.end.column -
1,
line: lastActualCellNode.position.end.line,
},
end: currentRow.position.end,
},
messageId: "missingCells",
data: {
actualCells: String(actualCellsLength),
expectedCells: String(expectedCellsLength),
Expand Down
187 changes: 177 additions & 10 deletions tests/rules/table-column-count.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,24 @@ ruleTester.run("table-column-count", rule, {
| abc | def |
| --- | --- |
`,
{
code: dedent`
| Header | Header |
| ------ | ------ |
| Cell | Cell |
| Cell | Cell |
`,
options: [{ checkMissingCells: true }],
},
{
code: dedent`
| Header | Header |
| ------ | ------ |
| Cell | |
| Cell | Cell |
`,
options: [{ checkMissingCells: true }],
},
],

invalid: [
Expand All @@ -99,7 +117,7 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 3,
column: 17,
Expand All @@ -116,7 +134,7 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "4", expectedCells: "2" },
line: 3,
column: 17,
Expand All @@ -133,7 +151,7 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "2", expectedCells: "1" },
line: 3,
column: 5,
Expand All @@ -155,7 +173,7 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 5,
column: 21,
Expand All @@ -173,7 +191,7 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 4,
column: 11,
Expand All @@ -191,7 +209,7 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 3,
column: 13,
Expand All @@ -209,15 +227,15 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 3,
column: 13,
endLine: 3,
endColumn: 23,
},
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 4,
column: 13,
Expand All @@ -236,15 +254,15 @@ ruleTester.run("table-column-count", rule, {
`,
errors: [
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 3,
column: 13,
endLine: 3,
endColumn: 23,
},
{
messageId: "inconsistentColumnCount",
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 5,
column: 13,
Expand All @@ -253,5 +271,154 @@ ruleTester.run("table-column-count", rule, {
},
],
},
{
code: dedent`
| Header | Header | Header |
| ------ | ------ | ------ |
| Cell | Cell |
`,
options: [{ checkMissingCells: true }],
errors: [
{
messageId: "missingCells",
data: { actualCells: "2", expectedCells: "3" },
line: 3,
column: 19,
endLine: 3,
endColumn: 20,
},
],
},
{
code: dedent`
| Col A | Col B | Col C |
| ----- | ----- | ----- |
| Cell | | Cell |
| Cell | Cell |
`,
options: [{ checkMissingCells: true }],
errors: [
{
messageId: "missingCells",
data: { actualCells: "2", expectedCells: "3" },
line: 4,
column: 17,
endLine: 4,
endColumn: 18,
},
],
},
{
code: dedent`
| Col A | Col B | Col C |
| ----- | ----- | ----- |
| Cell |
| Cell | Cell |
| Cell | Cell | Cell |
`,
options: [{ checkMissingCells: true }],
errors: [
{
messageId: "missingCells",
data: { actualCells: "1", expectedCells: "3" },
line: 3,
column: 9,
endLine: 3,
endColumn: 10,
},
{
messageId: "missingCells",
data: { actualCells: "2", expectedCells: "3" },
line: 4,
column: 17,
endLine: 4,
endColumn: 18,
},
],
},
{
code: dedent`
| Table |
| ----- |
| Cell | Cell |
| Cell |
| Cell | Cell |
`,
options: [{ checkMissingCells: true }],
errors: [
{
messageId: "extraCells",
data: { actualCells: "2", expectedCells: "1" },
line: 3,
column: 9,
endLine: 3,
endColumn: 18,
},
{
messageId: "extraCells",
data: { actualCells: "2", expectedCells: "1" },
line: 5,
column: 9,
endLine: 5,
endColumn: 18,
},
],
},
{
code: dedent`
| Table | Header |
| ----- | ------ |
| Cell | Cell | Cell |
| Cell |
| Cell | Cell |
`,
options: [{ checkMissingCells: true }],
errors: [
{
messageId: "extraCells",
data: { actualCells: "3", expectedCells: "2" },
line: 3,
column: 18,
endLine: 3,
endColumn: 28,
},
{
messageId: "missingCells",
data: { actualCells: "1", expectedCells: "2" },
line: 4,
column: 9,
endLine: 4,
endColumn: 10,
},
],
},
{
code: dedent`
| Table | Header | Header |
| ----- | ------ | ------ |
| Cell | Cell | Cell |
| Cell | Cell | Cell | Cell |
| Cell |
`,
options: [{ checkMissingCells: true }],
errors: [
{
messageId: "extraCells",
data: { actualCells: "4", expectedCells: "3" },
line: 4,
column: 27,
endLine: 4,
endColumn: 37,
},
{
messageId: "missingCells",
data: { actualCells: "1", expectedCells: "3" },
line: 5,
column: 9,
endLine: 5,
endColumn: 10,
},
],
},
],
});