Create and edit Obsidian Bases with views, filters, formulas

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, map, or kanban) 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. If it doesn't open as a base at all, check that Bases is turned on in Settings → Core plugins

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:
  formula_name: 'expression'

# Configure display names and settings for properties.
# Note properties need the `note.` prefix here, or the setting is ignored.
properties:
  note.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 | kanban
    name: "View Name"
    limit: 10                    # Optional: limit results
    groupBy:                     # Optional: group results
      property: property_name
      direction: ASC | DESC
    groupOrder:                  # Optional: only these groups, in this order
      - value_one
      - null                     # Files with no value for the groupBy property
    sort:                        # Optional: sort results (supports multiple properties)
      - property: property_name
        direction: ASC | DESC
    filters:                     # View-specific filters follow the same rules
      and:
        - 'status == "active"'
    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

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

In order, filters, groupBy, and sort, a note property can be written bare (author) or prefixed (note.author). In the top-level properties: section, always write note.author, because Obsidian ignores a bare key there and shows the raw name as the column header.

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. Slow in large vaults and doesn't refresh when the vault changes; prefer reversing the lookup with file.links
file.embeds	List	Embeds in the note
file.properties	Object	All frontmatter properties. Doesn't refresh when the vault changes
file.file	File	File object, only usable in specific functions

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, "")'

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.

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

Kanban View

Requires Obsidian 1.14+. Cards are grouped into columns by the groupBy property, which a kanban view needs. groupOrder sets which columns show and in what order; use null to include files with no value. Without groupOrder, every value gets a column. Dragging a card to another column updates that property in the note. Only Markdown notes can be moved, except when grouping by file.folder, where moving a card moves the file to that folder. When grouping by a formula or by a file property other than file.folder, cards and columns can't be moved and notes can't be created from a column.

views:
  - type: kanban
    name: "Projects"
    groupBy:
      property: note.status
      direction: ASC
    groupOrder:
      - Planned
      - In progress
      - Done
    order:
      - file.name
      - due_date

Map View

Requires latitude/longitude properties and the Maps community plugin.

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

Sorting

Sort results by one or more properties. Each sort entry specifies a property and direction, which must be uppercase ASC or DESC; an entry with any other value, or a sort written as a string, is silently ignored. Multiple sort entries are applied in order — the first entry is the primary sort key, subsequent entries break ties.

views:
  - type: table
    name: "Sorted Tasks"
    sort:
      - property: due
        direction: ASC
      - property: file.name
        direction: ASC
    order:
      - file.name
      - due
      - status

Sort options depend on the property type:

Property Type	ASC	DESC
Text	A→Z	Z→A
Number	0→9	9→0
Date	Old→New	New→Old

You can sort by any property including formulas (formula.my_formula), file properties (file.mtime), and note 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:
  note.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
    sort:
      - property: due
        direction: ASC
      - property: file.name
        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:
  note.author:
    displayName: Author
  formula.status_icon:
    displayName: "Status"
  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

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 a .base file

Embed an external .base file in any Markdown note:

![[MyBase.base]]

<!-- Specific view -->
![[MyBase.base#View Name]]

Embed inline with a code block

Bases can also be embedded inline directly inside a note using a base fenced code block. This is useful for note-level filters (e.g. using this.file.links) and avoids creating a separate .base file:

```base
filters:
  and:
    - file.hasTag("example")
views:
  - type: table
    name: Table
    order:
      - file.name
      - status
```

When embedded inline this way, the this keyword refers to the containing note, so you can build per-note views such as showing all notes linked from the current file.

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, "")'

displayName ignored, column shows the raw name: prefix note properties with note. in the properties: section.

# WRONG - displayName ignored, column header shows "status"
properties:
  status:
    displayName: Status

# CORRECT - column header shows "Status"
properties:
  note.status:
    displayName: Status

Empty displayName doesn't hide a header: displayName: "" falls back to the property name, the same as leaving it out, so formula.status_icon shows status_icon. Use a non-empty name such as displayName: "Status".

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"

References

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