const

Declares a constant with block level scope

Other: https://tc39.es/ecma262/#sec-let-and-const-declarations

Usage: 95.9% + 0.7% = 96.6%

Support summary

Notes

  1. const is recognized, but treated like var (no block scope, can be overwritten)
  2. const does not have block scope
  3. Only recognized when NOT in strict mode
  4. Supported correctly in strict mode, otherwise supported without block scope
  5. Not supported in for-in and for-of loops

Links

Full support table

IE

5.567891011
nnnnnna

Edge

121314151617187980818384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Firefox

233.53.6456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Chrome

4567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Safari

3.13.2455.166.177.1899.11010.11111.11212.11313.11414.11515.115.2-15.315.415.515.616.016.116.216.316.416.516.617.017.117.217.317.417.517.618.018.118.218.318.418.5TP
aaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Opera

99.5-9.610.0-10.110.510.61111.111.511.61212.11516171819202122232425262728293031323334353637383940414243444546474849505152535455565758606263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117
nnaaaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Safari on iOS

3.24.0-4.14.2-4.35.0-5.16.0-6.17.0-7.188.1-8.49.0-9.29.310.0-10.210.311.0-11.211.3-11.412.0-12.112.2-12.513.0-13.113.213.313.4-13.714.0-14.414.5-14.815.0-15.115.2-15.315.415.515.6-15.816.016.116.216.316.416.516.6-16.717.017.117.217.317.417.517.6-17.718.018.118.218.318.418.5
aaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Opera Mini

all
a

Android Browser

2.12.22.3344.14.2-4.34.44.4.3-4.4.4137
uuaaaaaaay

Blackberry Browser

710
aa

Opera Mobile

101111.111.51212.180
aaaaaay

Chrome for Android

137
y

Firefox for Android

139
y

IE Mobile

1011
ny

UC Browser for Android

15.5
y

Samsung Internet

45.0-5.46.2-6.47.2-7.48.29.210.111.1-11.212.013.014.015.016.017.018.019.0202122232425262728
ayyyyyyyyyyyyyyyyyyyyyyyy

QQ Browser

14.9
y

Baidu Browser

13.52
y

KaiOS Browser

2.53.0-3.1
yy

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