2024 05 04 handling typescript error object is possibly null in queryselector result - bizkite-co/handterm GitHub Wiki

original file name: Codeium Chat - pC0MXEwWFxkBNIG4VJnJPZVKbRRg9nqv.md summary: The user had a TypeScript error "Object is possibly 'null'." due to accessing properties on a potentially null value returned by document.querySelector. I explained the issue and provided a solution by adding a null check before accessing the properties of the result to avoid runtime errors. date: 2024-05-04T12:44

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User at 12:44 pm, May 4, 2024

Explain problem: Object is possibly 'null'.

Codeium at 12:44 pm, May 4, 2024

The issue "Object is possibly 'null'." arises in TypeScript because document.querySelector<HTMLDivElement>("div.content") can potentially return null, and accessing properties or methods on a potentially null value can lead to runtime errors.

To address this, you can perform a null check before accessing properties or methods on the result of document.querySelector<HTMLDivElement>("div.content") to ensure it's not null. This can be done like so:

const divContent = document.querySelector<HTMLDivElement>("div.content");
if (divContent) {
    // Safely use divContent here
    divContent.appendChild(this.chordSection);
}

By performing this null check, you avoid the "Object is possibly 'null'." issue and ensure safe access to the div.content element.

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