I need to extract a JSON string that sits inside a bigger string (I know, bad API response that I just have to deal with). Anyway I built a single regex to read everything inside {} and it works in all cases tested, except for the actual API response in the snippet below.

Any ideas why it's not working and how to make it work?

let dd = 'Error: Internal JSON-RPC error.\n{\n  "code": 3,\n  "message": "execution reverted: This limited season is sold out. Please wait for the next season.",\n  "data": "0x08c379a00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000004154686973206c696d6974656420736561736f6e20697320736f6c64206f75742e20506c65617365207761697420666f7220746865206e65787420736561736f6e2e00000000000000000000000000000000000000000000000000000000000000"\n}';

alert(RegExp(/{.*}/).exec(dd))

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

You need to add an s flag as the second argument to your RegExp constructor:

s - ("dotAll") Allows . to match newlines.

let dd = 'Error: Internal JSON-RPC error.\n{\n  "code": 3,\n  "message": "execution reverted: This limited season is sold out. Please wait for the next season.",\n  "data": "0x08c379a00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000004154686973206c696d6974656420736561736f6e20697320736f6c64206f75742e20506c65617365207761697420666f7220746865206e65787420736561736f6e2e00000000000000000000000000000000000000000000000000000000000000"\n}';

alert(RegExp('{.*}', 's').exec(dd))

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp

CodePudding user response：

The content is not matched between multiple lines, so you can use the /s modifier to include new lines. Also Regexp() is not needed when using regexp syntax (/{.*}/s is the same as Regexp('{.*}','s')):

alert(/{.*}/s.exec(dd))

let dd = 'Error: Internal JSON-RPC error.\n{\n  "code": 3,\n  "message": "execution reverted: This limited season is sold out. Please wait for the next season.",\n  "data": "0x08c379a00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000004154686973206c696d6974656420736561736f6e20697320736f6c64206f75742e20506c65617365207761697420666f7220746865206e65787420736561736f6e2e00000000000000000000000000000000000000000000000000000000000000"\n}';

alert(/{.*}/s.exec(dd))

<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

Try this expression which matches everything.

/\{[\s\S]*\}/.exec(dd)

The one you created didn't work because it contains linebreaks \n.

CodePudding user response：

With another approach using .match() will actually return the match against the string you're want to extract, which is inside {curly braces}. with two flags s to enable searching new lines and g for searching globally

dd.match(/\{(.*)?\}/sg)[0]

Result {\n "code": 3,\n "message": "execution reverted: T…0000000000000000000000000000000000000000000000"\n}