Performance

performance/assoc-many

Enabled by default	Version Added	Version Updated
false	1.10.0	1.10.0

Assoc takes multiple pairs but relies on seq stepping. This is slower than relying on multiple assoc invocations.

Examples

# bad
(assoc m :k1 1 :k2 2 :k3 3)

# good
(-> m
    (assoc :k1 1)
    (assoc :k2 2)
    (assoc :k3 3))

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performance/avoid-satisfies

Enabled by default	Version Added	Version Updated
false	1.10.0	1.10.0

Avoid use of satisfies? as it is extremely slow. Restructure your code to rely on protocols or other polymorphic forms.

Examples

# bad
(satisfies? Foo :bar)

Reference

• https://bsless.github.io/datahike-datalog-parser

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performance/get-in-literals

Enabled by default	Version Added	Version Updated
false	1.10.0	1.10.0

clojure.core/get-in is both polymorphic and relies on seq stepping, which has heavy overhead when the listed slots are keyword literals. Faster to call them as functions.

Examples

# bad
(get-in m [:some-key1 :some-key2 :some-key3])

# good
(-> m :some-key1 :some-key2 :some-key3)

---

performance/get-keyword

Enabled by default	Version Added	Version Updated
false	1.10.0	1.10.0

clojure.core/get is polymorphic and overkill if accessing a map with a keyword literal. The fastest is to fall the map itself as a function but that requires a nil check, so the safest fast method is to use the keyword as function.

Examples

# bad
(get m :some-key)

# good
(:some-key m)