javascript match and add string in dynamic Url

Question

I have a dynamic URL, which i want to append some string at last

 'http://staging.mydomain.name.com/test/7bb12c5f7b2f4f008261bea2d3f5abd2/200x200.png'

want to append "preview" before size (200x200.png which is also dynamic), something like below

'http://staging.mydomain.name.com/test/7bb12c5f7b2f4f008261bea2d3f5abd2/preview/200x200.png'

I have seen Javascript match to remove part of file name from URL - replace the last occurence but its not what i want.

Thanks

Answer 1

只需使用一个简单的正则表达式即可：

'http://.../200x200.png'.replace(/[^\/]+$/, 'preview/$&')

Answer 2

你可以像str.replace（/（/ \\ d + x \\ d +。）/，'/ preview $ 1'）