Obsidian Bases Skill#

Workflow#

1. Create the file: Create a .base file in the vault with valid YAML content
2. Define scope: Add filters to select which notes appear (by tag, folder, property, or date)
3. Add formulas (optional): Define computed properties in the formulas section
4. Configure views: Add one or more views ( table, cards, list, or map) with order specifying which properties to display
5. 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
6. 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.

yaml

# 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#

yaml

# 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#

OperatorDescription==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#

1. Note properties - From frontmatter: note.author or just author
2. File properties - File metadata: file.name, file.mtime, etc.
3. Formula properties - Computed values: formula.my_formula

File Properties Reference#

PropertyTypeDescriptionfile.nameStringFile namefile.basenameStringFile name without extensionfile.pathStringFull path to filefile.folderStringParent folder pathfile.extStringFile extensionfile.sizeNumberFile size in bytesfile.ctimeDateCreated timefile.mtimeDateModified timefile.tagsListAll tags in filefile.linksListInternal links in filefile.backlinksListFiles linking to this filefile.embedsListEmbeds in the notefile.propertiesObjectAll 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.

yaml

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, "")'

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.

FunctionSignatureDescriptiondate()``date(string): dateParse string to date ( YYYY-MM-DD HH:mm:ss)now()``now(): dateCurrent date and timetoday()``today(): dateCurrent date (time = 00:00:00)if()``if(condition, trueResult, falseResult?)Conditionalduration()``duration(string): durationParse duration stringfile()``file(path): fileGet file objectlink()``link(path, display?): LinkCreate 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.

yaml

# 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#

yaml

# 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#

yaml

views:
  - type: table
    name: "My Table"
    order:
      - file.name
      - status
      - due_date
    summaries:
      price: Sum
      count: Average

Cards View#

yaml

views:
  - type: cards
    name: "Gallery"
    order:
      - file.name
      - cover_image
      - description

List View#

yaml

views:
  - type: list
    name: "Simple List"
    order:
      - file.name
      - status

Map View#

Requires latitude/longitude properties and the Maps community plugin.

yaml

views:
  - type: map
    name: "Locations"
    # Map-specific settings for lat/lng properties

Default Summary Formulas#

NameInput TypeDescriptionAverageNumberMathematical meanMinNumberSmallest numberMaxNumberLargest numberSumNumberSum of all numbersRangeNumberMax - MinMedianNumberMathematical medianStddevNumberStandard deviationEarliestDateEarliest dateLatestDateLatest dateRangeDateLatest - EarliestCheckedBooleanCount of true valuesUncheckedBooleanCount of false valuesEmptyAnyCount of empty valuesFilledAnyCount of non-empty valuesUniqueAnyCount of unique values

Complete Examples#

Task Tracker Base#

yaml

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#

yaml

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

Daily Notes Index#

yaml

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:

markdown

![[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.

yaml

# 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.

yaml

# 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.

yaml

# 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.

yaml

# 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.

yaml

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

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

References#

• Bases Syntax
• Functions
• Views
• Formulas
• Complete Functions Reference