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Playing with Sorbet

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What

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Sorbet is a fast, powerful type checker designed for Ruby.

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Why

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Once upon a time

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We expose a public API

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Expecting params = { user: { first_name: "Luciano", last_name: "Sousa" } }

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We got a

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params = { user: "a" }

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TypeError (no implicit conversion of Symbol into Integer)

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NoMethodError (undefined method `where' for nil:NilClass)

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Let’s talk about Java

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Let’s talk about dynamic vs static typed languages

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• •

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• • •

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String javaString = new String(“I am a Java string”) ruby_string = “I am a Ruby string”

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Dynamic languages

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Ruby

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Examples

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begin do_something rescue StandardErro do_something_else end

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Tests

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Let's talk about Shopify

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~1500 devs

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~40 deploys/day

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~5 million req/min

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~83k req/sec ~170k req/sec peak

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Sorbet at Shopify

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~36 issues fixed

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~17 dead code never hit

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~16 name error

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~3 wrong args

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Maybe some millions

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Examples

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“I hate type annotations.”

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class UserHelper def name_length(name) name.length end end

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# typed: true class UserHelper def name_length(name) name.length end end

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# typed: true class UserHelper extend T::Sig def name_length(name) name.length end end

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# typed: true class UserHelper extend T::Sig sig { params(name: String).returns(Integer) } def name_length(name) name.length end end

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How it works

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Disclaimer

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# typed: true

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extend T::Sig

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sig { params(name: String).returns(Integer) }

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sig { params(name: String).returns(Integer) }

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Resources •

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Resources •

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Resources •

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Thanks!