<?xml version="1.0" encoding="utf-8" standalone="yes"?>Articles from October 2026 on PowerShell.org - Welcome Automaters!https://powershell.org/articles/2026/10/Recent content in Articles from October 2026 on PowerShell.org - Welcome Automaters!Hugoen-usBuild Vega-Lite HTML Reports with PowerShellhttps://powershell.org/articles/2026/10/build-vega-lite-html-reports-with-powershell/https://powershell.org/articles/2026/10/build-vega-lite-html-reports-with-powershell/Mon, 05 Oct 2026 00:00:00 +0000<p>PowerShell is good at acquiring data and turning it into objects. Vega-Lite is good at turning structured data into interactive graphics. A small function is enough to connect the two without adopting a reporting framework or opening a browser from the script.</p> <p>In this article, we download the <a href="https://allisonhorst.github.io/palmerpenguins/">Palmer Penguins</a> dataset, clean it with ordinary PowerShell, describe three views as one Vega-Lite specification, and save the finished report as an HTML file.</p><![CDATA[

PowerShell is good at acquiring data and turning it into objects. Vega-Lite is good at turning structured data into interactive graphics. A small function is enough to connect the two without adopting a reporting framework or opening a browser from the script.

In this article, we download thePalmer Penguins dataset, clean it with ordinary PowerShell, describe three views as one Vega-Lite specification, and save the finished report as an HTML file.

The key design choice is thatShow-VegaLite doesn’t decide what to do with the HTML. It returns the document to the pipeline:

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$reportSpec | Show-VegaLite -PageTitle'Palmer Penguins report' | Set-Content -Path ./penguins-report.html -Encoding utf8

That makes the renderer useful in a console script, scheduled job, CI pipeline, or notebook.

The finished report

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$dataUrl ='https://raw.githubusercontent.com/' +'allisonhorst/palmerpenguins/main/inst/extdata/penguins.csv'$penguins = Invoke-RestMethod -Uri$dataUrl | ConvertFrom-Csv | Where-Object {$_.bill_length_mm-ne'NA'-and$_.bill_depth_mm-ne'NA'-and$_.flipper_length_mm-ne'NA'-and$_.body_mass_g-ne'NA'-and$_.sex-ne'NA' } | ForEach-Object { [pscustomobject]@{ species =$_.species island =$_.island bill_length_mm = [double]$_.bill_length_mm bill_depth_mm = [double]$_.bill_depth_mm flipper_length_mm = [int]$_.flipper_length_mm body_mass_g = [int]$_.body_mass_g sex =$_.sex year = [int]$_.year } }

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$reportSpec = [ordered]@{'$schema' ='https://vega.github.io/schema/vega-lite/v6.json' data =@{ values =@($penguins) } spacing =24 vconcat =@(@{ width =760 height =150 title ='Observations by species' mark =@{ type ='bar'; cornerRadiusEnd =3 } encoding =@{ x =@{ field ='species' type ='nominal' title =$null sort ='-y' } y =@{ aggregate ='count' type ='quantitative' title ='Penguins' } color =@{ field ='species' type ='nominal' legend =$null } tooltip =@(@{ field ='species'; type ='nominal'; title ='Species' }@{ aggregate ='count'; type ='quantitative'; title ='Observations' } ) } }@{ hconcat =@(@{ width =365 height =300 title ='Bill dimensions' mark =@{ type ='point' filled =$true opacity =0.72 size =65 } encoding =@{ x =@{ field ='bill_length_mm' type ='quantitative' title ='Bill length (mm)' scale =@{ zero =$false } } y =@{ field ='bill_depth_mm' type ='quantitative' title ='Bill depth (mm)' scale =@{ zero =$false } } color =@{ field ='species' type ='nominal' title ='Species' } shape =@{ field ='sex' type ='nominal' title ='Sex' } } }@{ width =365 height =300 title ='Body mass distribution' mark =@{ type ='boxplot' extent ='min-max' size =34 } encoding =@{ x =@{ field ='species' type ='nominal' title =$null } y =@{ field ='body_mass_g' type ='quantitative' title ='Body mass (g)' scale =@{ zero =$false } } color =@{ field ='species' type ='nominal' legend =$null } } } ) } ) config =@{ view =@{ stroke =$null } axis =@{ labelColor ='#42506a' titleColor ='#27334a' gridColor ='#e6eaf0' } title =@{ anchor ='start' color ='#17233c' fontSize =16 } range =@{ category =@('#4c78a8','#f58518','#54a24b') } }}

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functionShow-VegaLite { [CmdletBinding()]param( [Parameter(Mandatory, ValueFromPipeline)] [System.Collections.IDictionary]$Spec, [string]$PageTitle ='Vega-Lite report', [ValidateSet('svg','canvas')] [string]$Renderer ='svg' )process {$specJson =$Spec | ConvertTo-Json -Depth100 -Compress$specBase64 = [Convert]::ToBase64String( [Text.Encoding]::UTF8.GetBytes($specJson) )$encodedTitle = [Net.WebUtility]::HtmlEncode($PageTitle)@"<!doctype html><html lang="en"><head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>$encodedTitle</title> <script src="https://cdn.jsdelivr.net/npm/vega@6.3.1"></script> <script src="https://cdn.jsdelivr.net/npm/vega-lite@6.4.3"></script> <script src="https://cdn.jsdelivr.net/npm/vega-embed@7.1.0"></script> <style> body { font-family: system-ui, sans-serif; margin: 2rem; } #vis { overflow-x: auto; } .error { color: #a61b1b; white-space: pre-wrap; } </style></head><body> <h1>$encodedTitle</h1> <div id="vis"></div> <script> const binary = atob("$specBase64"); const bytes = Uint8Array.from( binary, character => character.charCodeAt(0) ); const spec = JSON.parse(new TextDecoder().decode(bytes)); vegaEmbed("#vis", spec, { mode: "vega-lite", renderer: "$Renderer", actions: true }).catch(error => { const message = document.createElement("div"); message.className = "error"; message.textContent = error.stack || error.message; document.querySelector("#vis").replaceChildren(message); }); </script></body></html>"@ }}

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$outputPath = Join-Path$PWD'penguins-report.html'$reportSpec | Show-VegaLite -PageTitle'Palmer Penguins report' | Set-Content -Path$outputPath -Encoding utf8Get-Item$outputPath

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$reportSpec | Show-VegaLite | Display -MimeType'text/html'