Walking through the source code of an OSS library(ESLint)

Walking through the source code of an OSS library(ESLint)
'SPOUFOE&OHJOFFS-5 #FFS#BTI @kkeeth @kuwahara_jsri @kkeeth

Who am I const my_info = { Name: ‘Kuwahara KEETH
Kiyohito’, Company: ‘Yumemi Inc’, Position: ‘Servant Leader/Board’, Skills: ‘Riot.js/Next.js/Chit-chat’, }

Published

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🙇 Sorry … 🙇 This slide is written in English.
However, I am still learning English, and there may be some inappropriate expressions. Plz feedback for me called “Masakari” about my talk!!

Let’s start 😆

one day in development 💁

*NDPODFSOFEBCPVUUIFCFIBWJPS PGUIJTEFQFOEFOUMJCSBSZ🤔 *TOUUIBUBIVSEMFUPCFHJOXJUI $BOZPVSFBMMZSFBEJU me my “inner voice” -FUTSFBEUIFDPEFPGUIJTMJCSBSZ
me

:FT CVU*EPOUVOEFSTUBOEXIBU UIJTMJCSBSZJTEPJOHBOE .BZCFZPVEPOUIBWFUIFUJNF *TUIBUFTTFOUJBMMZXIBUZPVXBOUUP TPMWF me my “inner
voice” *UEFQFOETPOUIFUIJOH CVU JOUFSJNTVQQPSUDBOCFBMJBCJMJUZ MBUFSPO me

#VUFWFOJGZPVVOEFSTUBOEUIF TPVSDFDPEF XIBUEPZPVEPXJUI JU my “inner voice” *GJUTBCVH JUTCFTUUPDSFBUFBO JTTVFPS13
me 8IFOEPZPVUIJOLUIBUXJMMCF SFTPMWFE %PZPVUIJOLJUXJMMCF EPOFPOUJNF my “inner voice”

*GOPU UIFXPSTUUIBUDBOIBQQFOJT UIBUXFGPSLUIFSFQPTJUPSZBOE MPBEUIFDIBOHFT 8IPJTHPJOHUPNBJOUBJOJU   8IBUTUIFDPTU me my “inner
voice” )NNN*HVFTTTP0LBZ MFUT KVTUBTTVNFUIBUTUIFEFTJHOJUT TVQQPTFEUPCF😅 me

*GOPU UIFXPSTUUIBUDBOIBQQFOJT UIBUXFGPSLUIFSFQPTJUPSZBOE MPBEUIFDIBOHFT 8IPJTHPJOHUPNBJOUBJOJU   8IBUTUIFDPTU me my “inner
voice” )NNN*HVFTTTP0LBZ MFUT KVTUBTTVNFUIBUTUIFEFTJHOJUT TVQQPTFEUPCF😅 me none of your business ʘ(^o^)ʗ

I feel like I could learn more from reading codes
😆

Then, let's read the source code of ESLint!

*NBHFCZIUUQTFTMJOUPSH

Basically, we start from the module written in the main
of package.json💁

Next, let’s look at “bin” dir.

Only 3 helper functions and an executable function here💁

Next, let’s look at “lib/cli.js” fi le.

“cli.js” depends on “ESLint” module “ESLint” module depends on “CLIEngine”
module

I found out later that...

There exists a dependency map💁 *NBHFCZIUUQTHJUIVCDPNFTMJOUFTMJOUCMPCNBJOEPDTTSDEFWFMPQFSHVJEFBSDIJUFDUVSFEFQFOEFODZTWH

Knowledge 1: Overall design

Unified format for writing each module📝

Uni fi ed format for writing each module

util objects rich in methods📝

w /PEFKTlVUJMzPCKFDU w MJCSVMFTVUJMTBTUVUJMT w MJCTIBSFETUSJOHVUJMT w MJCTIBSFETBTUVUJMT NFUIPET SFHHFYQBUUFSOT
w MJCTPVSDFDPEFUPLFOTUPSFVUJMT the number of using methods

Knowledge 2: Node.js’s “util” module is useful

w VUJMJOTQFDU w VUJMGPSNBU w VUJMJOIFSJUT w VUJMMQSPNJTJGZ ˡ8IBUTVSQSJTFENFXBTUIJT Methods
used by ESLint

*NBHFCZIUUQTOPEFKTPSHBQJVUJMIUNM

Knowledge 3: Generator functions in JavaScript

Do you understand the following code?💁

Let's take a look at some sample codes💁

more detail, show MDN👉

An afterthought

An afterthought w /PUXSJUUFOJOUZQFTDSJQU UZQFEF fi OJUJPOTBSFXSJUUFO w "OZXBZ
UIFEPDVNFOUBUJPOJTFYUFOTJWF w +4%PDJTXFMMEPDVNFOUFE BTJTNE w %PDVNFOUBUJPOJTVTJOH&MFWFOUZKT UZ w 5PPMTGPS44( w %PDVNFOUBUJPOBQQJTFBTJFSUPWJFXUIBOUIFP ff i DJBMTJUF w 5IFSFBSFBMTPDPODFQUTPGMBZPVUBOEDPNQPOFOUT

Thoughts💁

Thoughts w 8FEPOUIBWFUPVOEFSTUBOEJUUPUBMZ👍 w %FTJHOJOHGBNPVTMJCSBSJFTJTBHSFBUMFBSOJOHFYQFSJFODF👍 w 8FDBOJNQSPWFNZTLJMMTGPSTVSF👍 w *GZPV fi
OEJUEJ ff i DVMU ZPVDBOSFBEJUXJUITPNFPOFFMTF👍 w *GZPVIBWFUSPVCMF JU`THPPEUPSFBEGSPNUIFUFTUDPEF👍

Walking through the source code of an OSS libra...

Walking through the source code of an OSS library(ESLint)

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