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Walking through the source code of an OSS libra...
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kkeeth
May 21, 2022
Programming
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Walking through the source code of an OSS library(ESLint)
kkeeth
May 21, 2022
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Transcript
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
OQNKTDPNdLLFFUI
🙇 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💁
None
Next, let’s look at “lib/cli.js” fi le.
None
“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
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?💁
None
Let's take a look at some sample codes💁
None
None
None
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
None
None
Thoughts💁
Thoughts w 8FEPOUIBWFUPVOEFSTUBOEJUUPUBMZ👍 w %FTJHOJOHGBNPVTMJCSBSJFTJTBHSFBUMFBSOJOHFYQFSJFODF👍 w 8FDBOJNQSPWFNZTLJMMTGPSTVSF👍 w *GZPV fi
OEJUEJ ff i DVMU ZPVDBOSFBEJUXJUITPNFPOFFMTF👍 w *GZPVIBWFUSPVCMF JU`THPPEUPSFBEGSPNUIFUFTUDPEF👍
None