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EventUtils.isLeftMouseButton fails in newer typescript versions #138

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#139
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EventUtils.isLeftMouseButton fails in newer typescript versions#138
#139
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0.1.0
@mayorovad

Description

@mayorovad
mayorovad
opened on Nov 20, 2022

Looks like in newer versions of Typescript (i think 4.9 and above) this code is failed to transpile:

maxGraph/packages/core/src/util/EventUtils.ts

Lines 124 to 134 in d30e3a2

export const isLeftMouseButton = (evt: MouseEvent) => {
// Special case for mousemove and mousedown we check the buttons
// if it exists because which is 0 even if no button is pressed
if ('buttons' in evt && (evt.type === 'mousedown' || evt.type === 'mousemove')) {
return evt.buttons === 1;
}
if ('which' in evt) {
return evt.which === 1;
}
return evt.button === 1;
};

error is Error: src/util/EventUtils.ts(133,14): error TS2339: Property 'button' does not exist on type 'never'

The easiest way to reproduce is to copy this method into https://www.typescriptlang.org/play?ts=next

⚠️ What is concerning, that this error somehow ended in build of #133

The way to fix this error with minimum changes is replace 'which' in evt with evt.which !== undefined at line 130.

Possible reason - which is marked as deprecated, so 'which' in evt check now casts evt to never type

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