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Walking through the source code of an OSS Libra...
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kkeeth
July 16, 2022
Programming
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Walking through the source code of an OSS Library(ESLint))
kkeeth
July 16, 2022
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Transcript
Walking through the source code of an OSS library(ESLint)
l4VNNFS+BWB4DSJQU'FTUJWBM0OMJOFz @kkeeth @kuwahara_jsri @kkeeth
While looking back on a day 💁
*`NBMFBEFOHJOFFSPSUFDIMFBE *WFDSFBUFEB13 QMFBTFSFWJFX me Team Member A 0,👍*`MMSFWJFXBOEGFFECBDLZPV me
5IFOVNCFSPGNFNCFSTBOE13TIBT JODSFBTFE TP*TIPVMEDPODFOUSBUFPOMZ POSFWJFXJOH OPUJNQMFNFOUJOH *WFDSFBUFEB13 QMFBTFSFWJFX me Team Member
B, C … 0,👍*`MMSFWJFXBOEGFFECBDLZPV me
1MFBTFSBUFUIJTDBOEJEBUFTDPEF Recruitment Personnel *`NBTFSWBOUMFBEFSPGPGBDSPTTFBDI FOHJOFFSJOHHSPVQ me *`NBNFNCFSPGUIF#PBSE me
me 0,👍*`MMSFWJFXBOEGFFECBDLZPV *TUPQQFEXSJUJOHNPSFBOENPSFDPEF *GZPVPOMZSFBEDPEF DBUDIJOHVQXJUIOFX UFDIOPMPHJFTTVDIBTMJCSBSJFTBOEGSBNFXPSLTUFOET UPCFTVQFS fi DJBM4Pʜ *GFFMmy
technical skills have declined… Voice of my heart
me 0,👍*`MMSFWJFXBOEGFFECBDLZPV *TUPQQFEXSJUJOHNPSFBOENPSFDPEF *GZPVPOMZSFBEDPEF DBUDIJOHVQXJUIOFX UFDIOPMPHJFTTVDIBTMJCSBSJFTBOEGSBNFXPSLTUFOET UPCFTVQFS fi DJBM4Pʜ *GFFMmy
technical skills have declined… Voice of my heart I've got to do something ʘ(^o^)ʗ
I feel like I could learn more from reading codes
😆
About me
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 😆
Then, let's read the source code of ESLint!
*NBHFCZIUUQTFTMJOUPSH
Basically, we start from the module written in the main
of package.json💁
This is the main one. This is a so-called controller
💁
This is the module that actually does the work 💁
As the name implies, it is a helper or preparation
for testing. It includes many things 💁
This one is just like the name. This is a
collection of processes that handle source code. 💁
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
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