Obsidian Bases

Obsidian Bases Skill

Workflow

Create the file: Create a .base file in the vault with valid YAML content
Define scope: Add filters to select which notes appear (by tag, folder, property, or date)
Add formulas (optional): Define computed properties in the formulas section
Configure views: Add one or more views (table, cards, list, or map) with order specifying which properties to display
Validate: Verify the file is valid YAML with no syntax errors. Check that all referenced properties and formulas exist. Common issues: unquoted strings containing special YAML characters, mismatched quotes in formula expressions, referencing formula.X without defining X in formulas
Test in Obsidian: Open the .base file in Obsidian to confirm the view renders correctly. If it shows a YAML error, check quoting rules below

Schema

Base files use the .base extension and contain valid YAML.

# Global filters apply to ALL views in the base
filters:
  # Can be a single filter string
  # OR a recursive filter object with exactly ONE key: and, or, or not
  and:
    - 'status == "active"'
    - not:
        - 'file.hasTag("archived")'

# Define formula properties that can be used across all views
formulas

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

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

Key Functions

Most commonly used functions. For the complete reference of all types (Date, String, Number, List, File, Link, Object, RegExp), see FUNCTIONS_REFERENCE.md (opens in a new tab).

Function	Signature	Description
`date()`	`date(string): date`	Parse string to date (`YYYY-MM-DD HH:mm:ss`)
`now()`	`now(): date`	Current date and time
`today()`	`today(): date`	Current date (time = 00:00:00)
`if()`	`if(condition, trueResult, falseResult?)`	Conditional
`duration()`	`duration(string): duration`	Parse duration string
`file()`	`file(path): file`	Get file object
`link()`	`link(path, display?): Link`	Create a link

Duration Type

When subtracting two dates, the result is a Duration type (not a number).

Duration Fields: duration.days, duration.hours, duration.minutes, duration.seconds, duration.milliseconds

IMPORTANT: Duration does NOT support .round(), .floor(), .ceil() directly. 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
"(date(due_date) - today()).days.round(0)"           # Rounded days

# 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
"now() + \"1 day\""       # Tomorrow
"today() + \"7d\""        # A week from today
"now() - file.ctime"      # Returns Duration
"(now() - file.ctime).days"  # Get days as number

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:

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:

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

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

Troubleshooting

YAML Syntax Errors

Unquoted special characters: Strings containing :, {, }, [, ], ,, &, *, #, ?, |, -, <, >, =, !, %, @, ` must be quoted.

# WRONG - colon in unquoted string
displayName: Status: Active

# CORRECT
displayName: "Status: Active"

Mismatched quotes in formulas: When a formula contains double quotes, wrap the entire formula in single quotes.

# WRONG - double quotes inside double quotes
formulas:
  label: "if(done, "Yes", "No")"

# CORRECT - single quotes wrapping double quotes
formulas:
  label: 'if(done, "Yes", "No")'

Common Formula Errors

Duration math without field access: Subtracting dates returns a Duration, not a number. Always access .days, .hours, etc.

# WRONG - Duration is not a number
"(now() - file.ctime).round(0)"

# CORRECT - access .days first, then round
"(now() - file.ctime).days.round(0)"

Missing null checks: Properties may not exist on all notes. Use if() to guard.

# WRONG - crashes if due_date is empty
"(date(due_date) - today()).days"

# CORRECT - guard with if()
'if(due_date, (date(due_date) - today()).days, "")'

Referencing undefined formulas: Ensure every formula.X in order or properties has a matching entry in formulas.

# This will fail silently if 'total' is not defined in formulas
order:
  - formula.total

# Fix: define it
formulas:
  total: "price * quantity"