PQM Stepper

A simple static tool that renames Power Query M steps using a standardised schema to improve code readability — avoiding #"Step Name" quoted identifiers.

Live site: https://filcuk.github.io/pqm-stepper/

What it does

Paste Power Query M code from the Advanced Editor and get back the same code with auto-generated step names replaced by short, readable identifiers.

Before:

let
    Source = Excel.CurrentWorkbook(){[Name="Sheet1"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Col", type text}}),
    #"Renamed Columns" = Table.RenameColumns(#"Changed Type",{{"Col", "Name"}}),
    #"Filter Rows 1" = Table.SelectRows(#"Renamed Columns", each true),
    #"Filter Rows 2" = Table.SelectRows(#"Filter Rows 1", each true)
in
    #"Filter Rows 2"

After:

let
    Source = Excel.CurrentWorkbook(){[Name="Sheet1"]}[Content],
    Type = Table.TransformColumnTypes(Source,{{"Col", type text}}),
    Rename = Table.RenameColumns(Type,{{"Col", "Name"}}),
    Filter1 = Table.SelectRows(Rename, each true),
    Filter2 = Table.SelectRows(Filter1, each true)
in
    Filter2

Numbering rules

When multiple steps map to the same short name:

Occurrences	Result
1	Filter
2+	Filter1, Filter2, …

Numbering follows step order in the let block, not Power Query's original suffix.

Configuring mappings

Edit app/mapping.json. Keys are the inner quoted step name (without #"..."); values are the target identifier:

{
  "Changed Type": "Type",
  "Renamed Columns": "Rename",
  "Filter Rows": "Filter",
  "Filtered Rows": "Filter"
}

Power Query uses past-tense names (Renamed Columns, Filtered Rows) — include both variants if your queries use either. Commit and push to update the live site.

Rename rules for quoted steps defined in the query:

Situation	Result
Key in mapping.json	Mapped name (e.g. Filter)
Navigation pattern detected	Workbook, Sheet, Navigate, or Table
No mapping, defined in query	Auto-sanitized PascalCase (e.g. My Custom Step → MyCustomStep)
External reference (not defined here)	Left as #"..." unchanged

Dynamic mappings (* wildcard)

Some step types include an object name in the target identifier. Use * as a placeholder in the mapping value:

{
  "Added Custom": "Add*",
  "Added Conditional Column": "Add*",
  "Invoked Custom Function": "Invoke*"
}

The object name is parsed from the step's M expression:

Step type	Extracted from	Example output
Added Custom / Added Conditional Column	Column name in Table.AddColumn	AddUserName
Duplicated Column	Source column in Table.DuplicateColumn	AddUserName
Invoked Custom Function	Function name on the RHS	InvokeGetID

If the object name cannot be parsed, the * is dropped (e.g. Add* → Add) and a warning is shown.

Duplicate resolved names still get numbered (AddUserName1, AddUserName2).

Navigation steps

Some steps are detected automatically from their M expression (no mapping entry needed):

Pattern	Step name	Example
Excel.Workbook(...)	Workbook	Opening an Excel file
{[..., Kind="Sheet"]}[Data]	Sheet	Selecting a worksheet
{[..., Schema=..., Item=...]}[Data]	Navigate	Selecting a lakehouse / SQL schema table
{[..., entity=...]}[Data]	Table	Selecting a dataflow / entity table

Dataflow example:

Source = PayrollAgency_DF,
#"Agency Payroll - Neuven_" = Source{[entity="Agency Payroll - Neuven",version=""]}[Data],

→ Table = Source{[entity="Agency Payroll - Neuven",version=""]}[Data],

Excel example:

Source = Excel.Workbook(File.Contents("file.xlsx"), null, true),
Sheet1_Sheet = Source{[Item="Sheet1",Kind="Sheet"]}[Data],

→ Workbook = Excel.Workbook(...), Sheet = Source{...}[Data],

Duplicate navigation steps use the same numbering rules (Sheet1, Sheet2).

Local preview

ES modules require a local server (opening index.html directly will block fetch of mapping.json):

npx serve .

Then open http://localhost:3000.

GitHub Pages deployment

The site entry point is index.html at the repo root; app code lives in app/. GitHub Pages serves index.html as the homepage — if you see this README instead, Pages is misconfigured.

GitHub Actions (recommended):

1. Push to main (includes .github/workflows/pages.yml).
2. In repo Settings → Pages → Build and deployment, set Source to GitHub Actions.
3. After the workflow runs, the site is at https://<username>.github.io/pqm-stepper/.

Deploy from branch (alternative):

1. In Settings → Pages, set Source to Deploy from a branch.
2. Choose branch main and folder / (root) — index.html at the repo root is served instead of this README.

The workflow stages index.html plus the app/ folder into a clean artifact (README and other repo files are not published).

Project structure

index.html        # Site entry point (GitHub Pages homepage)
.nojekyll         # Skip Jekyll processing
app/
  main.js         # UI wiring and event handlers
  m-utils.js      # Shared M regex helpers
  styles.css      # Layout and theme
  transform.js    # Rename logic (pure, no DOM)
  highlight.js    # Prism M syntax + step highlighting
  editor.js       # Contenteditable caret helpers
  example.js      # Sample query for "Load example"
  mapping.json    # Step name schema
  vendor/prism/   # Prism.js + Power Query grammar (vendored)

License

MIT — see LICENSE.