Obsidian Bases Skill
This skill enables skills-compatible agents to create and edit valid Obsidian Bases (.base files) including views, filters, formulas, and all related configurations.
Overview
Obsidian Bases are YAML-based files that define dynamic views of notes in an Obsidian vault. A Base file can contain multiple views, global filters, formulas, property configurations, and custom summaries.
File Format
Base files use the .base extension and contain valid YAML. They can also be embedded in Markdown code blocks.
Complete Schema
# Global filters apply to ALL views in the base
filters:
# Can be a single filter string
# OR a recursive filter object with and/or/not
and: []
or: []
not: []
# Define formula properties that can be used across all views
formulas:
formula_name: 'expression'
# Configure display names and settings for properties
properties:
property_name:
displayName: "Display Name"
formula.formula_name:
displayName: "Formula Display Name"
file.ext:
displayName: "Extension"
# Define custom summary formulas
summaries:
custom_summary_name: 'values.mean().round(3)'
# Define one or more views
views:
- type: table | cards | list | map
name: "View Name"
limit: 10 # Optional: limit results
groupBy: # Optional: group results
property: property_name
direction: ASC | DESC
filters: # View-specific filters
and: []
order: # Properties to display in order
- file.name
- property_name
- formula.formula_name
summaries: # Map properties to summary formulas
property_name: Average
Filter Syntax
Filters narrow down results. They can be applied globally or per-view.
Filter Structure
# Single filter
filters: 'status == "done"'
# AND - all conditions must be true
filters:
and:
- 'status == "done"'
- 'priority > 3'
# OR - any condition can be true
filters:
or:
- 'file.hasTag("book")'
- 'file.hasTag("article")'
# NOT - exclude matching items
filters:
not:
- 'file.hasTag("archived")'
# Nested filters
filters:
or:
- file.hasTag("tag")
- and:
- file.hasTag("book")
- file.hasLink("Textbook")
- not:
- file.hasTag("book")
- file.inFolder("Required Reading")
Filter Operators
| Operator | Description |
|---|
== | equals |
!= | not equal |
> | greater than |
< | less than |
>= | greater than or equal |
<= | less than or equal |
&& | logical and |
|| | logical or |
| ! | logical not |
Properties
Three Types of Properties
- Note properties - From frontmatter:
note.author or just author
- File properties - File metadata:
file.name, file.mtime, etc.
- Formula properties - Computed values:
formula.my_formula
File Properties Reference
| Property | Type | Description |
|---|
file.name | String | File name |
file.basename | String | File name without extension |
file.path | String | Full path to file |
file.folder | String | Parent folder path |
file.ext | String | File extension |
file.size | Number | File size in bytes |
file.ctime | Date | Created time |
file.mtime | Date | Modified time |
file.tags | List | All tags in file |
file.links | List | Internal links in file |
file.backlinks | List | Files linking to this file |
file.embeds | List | Embeds in the note |
file.properties | Object | All frontmatter properties |
The this Keyword
- In main content area: refers to the base file itself
- When embedded: refers to the embedding file
- In sidebar: refers to the active file in main content
Formula Syntax
Formulas compute values from properties. Defined in the formulas section.
formulas:
# Simple arithmetic
total: "price * quantity"
# Conditional logic
status_icon: 'if(done, "✅", "⏳")'
# String formatting
formatted_price: 'if(price, price.toFixed(2) + " dollars")'
# Date formatting
created: 'file.ctime.format("YYYY-MM-DD")'
# Calculate days since created (use .days for Duration)
days_old: '(now() - file.ctime).days'
# Calculate days until due date
days_until_due: 'if(due_date, (date(due_date) - today()).days, "")'
Functions Reference
Global Functions
| Function | Signature | Description |
|---|
date() | date(string): date | Parse string to date. Format: YYYY-MM-DD HH:mm:ss |
duration() | duration(string): duration | Parse duration string |
now() | now(): date | Current date and time |
today() | today(): date | Current date (time = 00:00:00) |
if() | if(condition, trueResult, falseResult?) | Conditional |
min() | min(n1, n2, ...): number | Smallest number |
max() | max(n1, n2, ...): number | Largest number |
number() | number(any): number | Convert to number |
link() | link(path, display?): Link | Create a link |
list() | list(element): List | Wrap in list if not already |
file() | file(path): file | Get file object |
image() | image(path): image | Create image for rendering |
icon() | icon(name): icon | Lucide icon by name |
html() | html(string): html | Render as HTML |
escapeHTML() | escapeHTML(string): string | Escape HTML characters |
Any Type Functions
| Function | Signature | Description |
|---|
isTruthy() | any.isTruthy(): boolean | Coerce to boolean |
isType() | any.isType(type): boolean | Check type |
toString() | any.toString(): string | Convert to string |
Date Functions & Fields
Fields: date.year, date.month, date.day, date.hour, date.minute, date.second, date.millisecond
| Function | Signature | Description |
|---|
date() | date.date(): date | Remove time portion |
format() | date.format(string): string | Format with Moment.js pattern |
time() | date.time(): string | Get time as string |
relative() | date.relative(): string | Human-readable relative time |
isEmpty() | date.isEmpty(): boolean | Always false for dates |
Duration Type
When subtracting two dates, the result is a Duration type (not a number). Duration has its own properties and methods.
Duration Fields:
| Field | Type | Description |
|---|
duration.days | Number | Total days in duration |
duration.hours | Number | Total hours in duration |
duration.minutes | Number | Total minutes in duration |
duration.seconds | Number | Total seconds in duration |
duration.milliseconds | Number | Total milliseconds in duration |
IMPORTANT: Duration does NOT support .round(), .floor(), .ceil() directly. You must access a numeric field first (like .days), then apply number functions.
# CORRECT: Calculate days between dates
"(date(due_date) - today()).days" # Returns number of days
"(now() - file.ctime).days" # Days since created
# CORRECT: Round the numeric result if needed
"(date(due_date) - today()).days.round(0)" # Rounded days
"(now() - file.ctime).hours.round(0)" # Rounded hours
# WRONG - will cause error:
# "((date(due) - today()) / 86400000).round(0)" # Duration doesn't support division then round
Date Arithmetic
# Duration units: y/year/years, M/month/months, d/day/days,
# w/week/weeks, h/hour/hours, m/minute/minutes, s/second/seconds
# Add/subtract durations
"date + \"1M\"" # Add 1 month
"date - \"2h\"" # Subtract 2 hours
"now() + \"1 day\"" # Tomorrow
"today() + \"7d\"" # A week from today
# Subtract dates returns Duration type
"now() - file.ctime" # Returns Duration
"(now() - file.ctime).days" # Get days as number
"(now() - file.ctime).hours" # Get hours as number
# Complex duration arithmetic
"now() + (duration('1d') * 2)"
String Functions
Field: string.length
| Function | Signature | Description |
|---|
contains() | string.contains(value): boolean | Check substring |
containsAll() | string.containsAll(...values): boolean | All substrings present |
containsAny() | string.containsAny(...values): boolean | Any substring present |
startsWith() | string.startsWith(query): boolean | Starts with query |
endsWith() | string.endsWith(query): boolean | Ends with query |
isEmpty() | string.isEmpty(): boolean | Empty or not present |
lower() | string.lower(): string | To lowercase |
title() | string.title(): string | To Title Case |
trim() | string.trim(): string | Remove whitespace |
replace() | string.replace(pattern, replacement): string | Replace pattern |
repeat() | string.repeat(count): string | Repeat string |
reverse() | string.reverse(): string | Reverse string |
slice() | string.slice(start, end?): string | Substring |
split() | string.split(separator, n?): list | Split to list |
Number Functions
| Function | Signature | Description |
|---|
abs() | number.abs(): number | Absolute value |
ceil() | number.ceil(): number | Round up |
floor() | number.floor(): number | Round down |
round() | number.round(digits?): number | Round to digits |
toFixed() | number.toFixed(precision): string | Fixed-point notation |
isEmpty() | number.isEmpty(): boolean | Not present |
List Functions
Field: list.length
| Function | Signature | Description |
|---|
contains() | list.contains(value): boolean | Element exists |
containsAll() | list.containsAll(...values): boolean | All elements exist |
containsAny() | list.containsAny(...values): boolean | Any element exists |
filter() | list.filter(expression): list | Filter by condition (uses value, index) |
map() | list.map(expression): list | Transform elements (uses value, index) |
reduce() | list.reduce(expression, initial): any | Reduce to single value (uses value, index, acc) |
flat() | list.flat(): list | Flatten nested lists |
join() | list.join(separator): string | Join to string |
reverse() | list.reverse(): list | Reverse order |
slice() | list.slice(start, end?): list | Sublist |
sort() | list.sort(): list | Sort ascending |
unique() | list.unique(): list | Remove duplicates |
isEmpty() | list.isEmpty(): boolean | No elements |
File Functions
| Function | Signature | Description |
|---|
asLink() | file.asLink(display?): Link | Convert to link |
hasLink() | file.hasLink(otherFile): boolean | Has link to file |
hasTag() | file.hasTag(...tags): boolean | Has any of the tags |
hasProperty() | file.hasProperty(name): boolean | Has property |
inFolder() | file.inFolder(folder): boolean | In folder or subfolder |
Link Functions
| Function | Signature | Description |
|---|
asFile() | link.asFile(): file | Get file object |
linksTo() | link.linksTo(file): boolean | Links to file |
Object Functions
| Function | Signature | Description |
|---|
isEmpty() | object.isEmpty(): boolean | No properties |
keys() | object.keys(): list | List of keys |
values() | object.values(): list | List of values |
Regular Expression Functions
| Function | Signature | Description |
|---|
matches() | regexp.matches(string): boolean | Test if matches |
View Types
Table View
views:
- type: table
name: "My Table"
order:
- file.name
- status
- due_date
summaries:
price: Sum
count: Average
Cards View
views:
- type: cards
name: "Gallery"
order:
- file.name
- cover_image
- description
List View
views:
- type: list
name: "Simple List"
order:
- file.name
- status
Map View
Requires latitude/longitude properties and the Maps community plugin.
views:
- type: map
name: "Locations"
# Map-specific settings for lat/lng properties
Default Summary Formulas
| Name | Input Type | Description |
|---|
Average | Number | Mathematical mean |
Min | Number | Smallest number |
Max | Number | Largest number |
Sum | Number | Sum of all numbers |
Range | Number | Max - Min |
Median | Number | Mathematical median |
Stddev | Number | Standard deviation |
Earliest | Date | Earliest date |
Latest | Date | Latest date |
Range | Date | Latest - Earliest |
Checked | Boolean | Count of true values |
Unchecked | Boolean | Count of false values |
Empty | Any | Count of empty values |
Filled | Any | Count of non-empty values |
Unique | Any | Count of unique values |
Complete Examples
Task Tracker Base
filters:
and:
- file.hasTag("task")
- 'file.ext == "md"'
formulas:
days_until_due: 'if(due, (date(due) - today()).days, "")'
is_overdue: 'if(due, date(due) < today() && status != "done", false)'
priority_label: 'if(priority == 1, "🔴 High", if(priority == 2, "🟡 Medium", "🟢 Low"))'
properties:
status:
displayName: Status
formula.days_until_due:
displayName: "Days Until Due"
formula.priority_label:
displayName: Priority
views:
- type: table
name: "Active Tasks"
filters:
and:
- 'status != "done"'
order:
- file.name
- status
- formula.priority_label
- due
- formula.days_until_due
groupBy:
property: status
direction: ASC
summaries:
formula.days_until_due: Average
- type: table
name: "Completed"
filters:
and:
- 'status == "done"'
order:
- file.name
- completed_date
Reading List Base
filters:
or:
- file.hasTag("book")
- file.hasTag("article")
formulas:
reading_time: 'if(pages, (pages * 2).toString() + " min", "")'
status_icon: 'if(status == "reading", "📖", if(status == "done", "✅", "📚"))'
year_read: 'if(finished_date, date(finished_date).year, "")'
properties:
author:
displayName: Author
formula.status_icon:
displayName: ""
formula.reading_time:
displayName: "Est. Time"
views:
- type: cards
name: "Library"
order:
- cover
- file.name
- author
- formula.status_icon
filters:
not:
- 'status == "dropped"'
- type: table
name: "Reading List"
filters:
and:
- 'status == "to-read"'
order:
- file.name
- author
- pages
- formula.reading_time
Project Notes Base
filters:
and:
- file.inFolder("Projects")
- 'file.ext == "md"'
formulas:
last_updated: 'file.mtime.relative()'
link_count: 'file.links.length'
summaries:
avgLinks: 'values.filter(value.isType("number")).mean().round(1)'
properties:
formula.last_updated:
displayName: "Updated"
formula.link_count:
displayName: "Links"
views:
- type: table
name: "All Projects"
order:
- file.name
- status
- formula.last_updated
- formula.link_count
summaries:
formula.link_count: avgLinks
groupBy:
property: status
direction: ASC
- type: list
name: "Quick List"
order:
- file.name
- status
Daily Notes Index
filters:
and:
- file.inFolder("Daily Notes")
- '/^\d{4}-\d{2}-\d{2}$/.matches(file.basename)'
formulas:
word_estimate: '(file.size / 5).round(0)'
day_of_week: 'date(file.basename).format("dddd")'
properties:
formula.day_of_week:
displayName: "Day"
formula.word_estimate:
displayName: "~Words"
views:
- type: table
name: "Recent Notes"
limit: 30
order:
- file.name
- formula.day_of_week
- formula.word_estimate
- file.mtime
Embedding Bases
Embed in Markdown files:
![[MyBase.base]]
<!-- Specific view -->
![[MyBase.base#View Name]]
YAML Quoting Rules
- Use single quotes for formulas containing double quotes:
'if(done, "Yes", "No")'
- Use double quotes for simple strings:
"My View Name"
- Escape nested quotes properly in complex expressions
Common Patterns
Filter by Tag
filters:
and:
- file.hasTag("project")
Filter by Folder
filters:
and:
- file.inFolder("Notes")
Filter by Date Range
filters:
and:
- 'file.mtime > now() - "7d"'
Filter by Property Value
filters:
and:
- 'status == "active"'
- 'priority >= 3'
Combine Multiple Conditions
filters:
or:
- and:
- file.hasTag("important")
- 'status != "done"'
- and:
- 'priority == 1'
- 'due != ""'
References
