Why string replace in JS doesn't replace all characters [duplicate]

Question

"-x-x+x".replace('-', '+')

equals

"+x-x+x"

why isn't the second - replaced?

.replace only replace the first instance(character). to replace all instances you have to use regex.. console.log('-x-x+x'.replace(/-/g, '+')); — wakakak
– wakakak, Commented Jan 22, 2020 at 22:01
Searching StackOverflow for "[javascript] replace all instances" pulls up many duplicate posts asking essentially the same question. — Taplar
– Taplar, Commented Jan 22, 2020 at 22:08

Alastair · Accepted Answer · 2020-01-22 22:02:16Z

2

.replace only replaces the first instance it finds. To replace all of them, use a regex:

"-x-x+x".replace(/-/g, '+')

Note the /g at the end of the regex: it indicates "global" mode. Without it you'll still only replace the first instance.

answered Jan 22, 2020 at 22:02

Alastair

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1 Comment

Thanks for this, I was trying to find what the /g meant.

Addis · Accepted Answer · 2020-01-22 22:02:45Z

1

Convert it to regex to replace all.

console.log("-x-x+x".replace(/-/g, '+'))

answered Jan 22, 2020 at 22:02

Addis

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customcommander · Accepted Answer · 2020-01-23 00:11:44Z

1

This is explained in the documentation for String#replace:

Use a regular expression:

'-x-x+x'.replace(/-/g, '+')
//=> "+x+x+x"

answered Jan 22, 2020 at 22:07

customcommander

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