JAVASCRIPT // 2026
A TALK ON
ARRAY
TRANSFORMATION.
The nine methods you'll use every day — map, filter,
reduce, and the rest — and where they actually show up
in real codebases. 15 MIN · BEGINNER 20
SLIDES
ARRAY TRANSFORMATIONS 2026
,02 / WHY
// 02 — WHY ARRAYS MATTER
EVERY APP IS A LIST OF THINGS.
FRONTEND BACKEND STATE I/O
Posts in a feed. Rows in a Rows from SQL. Records Form fields. Chat history. CSV lines. File paths. Log
table. Items in a cart. from an API. Queue jobs. Undo stack. entries.
WHY ARRAYS MATTER 02
, 03 / AGENDA
// 03 — AGENDA
WHAT WE'LL COVER
mutating vs not find · some · every
FOUNDATIONS 01 SEARCH 06
ITERATION 02 forEach flat · sort · slice
RESHAPE 07
TRANSFORM 03 map
SPREAD 08 ...destructure
NARROW 04 filter
CHAINING 09 pipelines
COLLAPSE 05 reduce
IN THE WILD 10 real codebases
AGENDA 03
A TALK ON
ARRAY
TRANSFORMATION.
The nine methods you'll use every day — map, filter,
reduce, and the rest — and where they actually show up
in real codebases. 15 MIN · BEGINNER 20
SLIDES
ARRAY TRANSFORMATIONS 2026
,02 / WHY
// 02 — WHY ARRAYS MATTER
EVERY APP IS A LIST OF THINGS.
FRONTEND BACKEND STATE I/O
Posts in a feed. Rows in a Rows from SQL. Records Form fields. Chat history. CSV lines. File paths. Log
table. Items in a cart. from an API. Queue jobs. Undo stack. entries.
WHY ARRAYS MATTER 02
, 03 / AGENDA
// 03 — AGENDA
WHAT WE'LL COVER
mutating vs not find · some · every
FOUNDATIONS 01 SEARCH 06
ITERATION 02 forEach flat · sort · slice
RESHAPE 07
TRANSFORM 03 map
SPREAD 08 ...destructure
NARROW 04 filter
CHAINING 09 pipelines
COLLAPSE 05 reduce
IN THE WILD 10 real codebases
AGENDA 03
