VS Code Extension: Insert Sequences (InsertSeq formarly Insertnums)
May 16, 2026 · View on GitHub
Insert Sequences is a small VS Code extension that helps you generate and insert various kinds of sequences into one or more cursors. It supports numeric sequences, alphabetic sequences, dates, user-defined or predefined lists, and inline JavaScript expressions. The syntax is compact and powerful, allowing repetition, stepping, frequency control, custom formats, stop expressions, and more.
All examples in this document are shown as GIF file.
Multi-cursor example (5 cursors)
With five empty cursors, start insertseq and you will see a preview of numbers 1 to 5 (the default start is 1).
If you type 3, the preview updates to 3–7. Pressing Enter inserts those numbers:
Change the step
Use :<number> or step:<number> to set the increment. The step: form requires a word boundary (space or comma) before it (for example, 10 step:2 works; 10step:2 does not).
Input: 10:2 (or 10 step:2) with 5 selections → output:
Repeat sequence after a fixed number of insertions
Use # or rep: / repeat: / repetition: to define the cycle length.
Input: 1#5 with 10 selections → output:
Repeat each value multiple times (frequency)
Use * or freq: / frequency: to repeat each logical value several times.
Input: 1 freq:2 with 10 selections → output:
Startover (overall cycle length)
Use ## or startover: / startagain: to restart the entire emitted stream after N emitted items.
Input: 1 rep:2 freq:3 startover:7 (short: 1#2*3##7) with 13 selections → output:
Formatting numbers
Formatting uses d3-format style. Example: zero-pad to width 3 with ~03d.
Input: 1~03d with 5 selections → output:
Stop expression
Use @ or stopif: / stopexpr: / stopexpression: to stop insertion based on a boolean expression. Use placeholders such as i for the current index (0-based).
Input: 1 stopif:(i>5) with many selections will stop when i > 5 (when the number would be 7).
During preview no new lines are inserted; the preview shows future insertions on the last selected line.
Alphabetic sequences
Alpha sequences use the configured alphabet (default a–z). All characters in the alphabet must be unique. If you have not defined a custom alphabet, the extension uses the default a–z alphabet (case handled by options).
Input: a with 5 selections → output:
Formatting alphabetic sequences
String formatting supports padding and alignment. Example: right-align in width 10 with ~>10.
Input: a~>10 with 5 selections → output:
Use ~w to enable wrap behavior (for example, z~w yields z, a, b, ... if configured).
Date sequences
Date sequences start with % followed by a date (for example, yyyy-mm-dd) or a quoted date string. Steps support days (default), weeks, months, or years. You can specify a language for formatting with lang:.
Input: %2025-03-02:1w~lang:de with 5 selections → output:
Expressions
Use the pipe | to create a sequence from an inline JavaScript expression. The expression is evaluated for each emission; parentheses or quotes are recommended for clarity.
Input: |(i>0?p * 2:1) with 5 selections → output:
Inline lists (Own sequences)
Provide a list inline using square brackets. Items are treated as a circular list.
Input: [Jan, Feb,Mar] with 5 selections → output:
Predefined lists
Predefined lists come from your configuration setting (insertseq.mysequences). Use the ; prefix to reference them.
Given configuration:
"insertseq.mysequences": [
["Jan","Feb","Mär","Apr","Mai","Jun","Jul","Aug","Sep","Okt","Nov","Dez"],
["foo","bar","foz"]
]
Input: ;Mär with 5 selections → output:
Predefined functions
Predefined functions come from your configuration settings (insertseq.myfunctions). Use = to reference them, followed by the number (1-based) of the function you want to use.
Given configuration:
"insertseq.myfunctions": [
"(i, start=1, step=1) => start + (i ** step)",
"(i) => Math.PI.toString().split('').splice(i,1)"
]
Input: =2 with 5 selections → output:
Quoted Template
Use quoted templates if you want to insert text beside the sequence.
Input: "Template string with numbers {}" 3:7@i>5 with 13 selections → output:
Backtick Template
Alternative, and if you want to insert multiple sequences in one input and text, you can use backtick templates.
Input: `Hello backticks {3:5} and more {h:2}` with 15 selections → output:
