🛡️strict mode
🚧 施工中
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🚧 施工中
Last updated
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Was this helpful?
JS ⟩ concepts ⟩ environment ⟩ JS engine ⟩ mode ⟩ strict
🛡️ always use strict mode❗ (👉 see why)
a way to opt in to a restricted variant of JavaScript, thereby implicitly opting-out of "sloppy mode".
in strict mode:
is local to the .
JS is lenient with , strict with .
, even in ❗
referencing a outside the block:
: ✅ / initialized to (in outer
/ always works in ❗️
strict mode: ⛔ ReferenceError (invisible in outer scope)❗