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ViewsApplescript: Safari "Do Javascript" No Longer Returns Booleans?
This used to return either true or false:
tell application "Safari" to do JavaScript "document.querySelector(\"video\") == null" in document 1
However, now, on macOS 12.0.1 on an M1 MBP, it doesn't seem to return anything (missing value) and the following convoluted wrapper seems necessary to get the former result:
tell application "Safari"
set result to do JavaScript "if (document.querySelector(\"video\") == null) {
1
} else {
0
}" in document 1
return result is 1
end tell
Another weird thing is that it's only booleans that don't get returned. The following returns 3.0:
tell application "Safari" to do JavaScript "3" in document 1
Any idea what changed? Is there a better way to get the boolean result back?
Here is what my Safari Develop tab looks like in case any of those settings are relevant:
1 answers
Answer question0
I still don't know why the issue is happening, but here's a temporary workaround in case it helps:
tell application "Safari"
set result to do JavaScript "try {
var jsResult = document.querySelector(\"video\").paused;
switch (jsResult) {
case true:
jsResult = 'js2as-true';
break;
case false:
jsResult = 'js2as-false';
}
jsResult
}
catch(err) {
'js2as-error' + err.message
}" in document 1
if (result = "js2as-true") then
return true
else if (result = "js2as-false") then
return false
else if (result starts with "js2as-error") then
set errMsg to text 12 thru -1 of result
error errMsg
else
return result
end if
end tell
One limitation is that it's hard to make generic because you need to explicitly store the return value from the appropriate statement. Another approach might be to insert the script into an anonymous function, but then you'd have to explicitly return aValue