valueExists

Category: Registry Operations

Namespace: web.registry.valueExists

Description

Checks whether a specific value exists within a registry key under HKEY_CURRENT_USER.

Syntax

const exists = await web.registry.valueExists({
    keyPath: 'Software\\MyApp',
    valueName: 'Setting'
});

Parameters

• keyPath (required) - Registry key path under HKEY_CURRENT_USER
• valueName (required) - Name of the registry value to check
• rootKey (optional) - Currently ignored; always uses HKEY_CURRENT_USER

Returns

Promise<boolean> - Returns a promise that resolves with true if the value exists, false otherwise

Examples

Simple example

const exists = await web.registry.valueExists({
    keyPath: 'Software\\MyApp',
    valueName: 'Username'
});

if (exists) {
    console.log('Username is saved');
} else {
    console.log('No username saved');
}

Conditional reading

const valueName = 'LastOpenedFile';
const exists = await web.registry.valueExists({
    keyPath: 'Software\\MyApp',
    valueName: valueName
});

if (exists) {
    const filePath = await web.registry.readValue({
        keyPath: 'Software\\MyApp',
        valueName: valueName
    });
    console.log('Last file:', filePath);
} else {
    console.log('No previous file');
}

Check multiple settings

const settings = ['Theme', 'Language', 'FontSize'];
const keyPath = 'Software\\MyApp\\Settings';

for (const setting of settings) {
    const exists = await web.registry.valueExists({
        keyPath: keyPath,
        valueName: setting
    });
    console.log(`${setting}: ${exists ? 'saved' : 'not set'}`);
}

Use Cases

• Check if a specific setting has been saved
• Verify value exists before reading
• Distinguish between empty string and non-existent value
• Validate registry structure
• Check for optional configuration values

Notes

• Always operates under HKEY_CURRENT_USER root key
• Returns false if the key doesn't exist
• Returns false if the value doesn't exist
• More precise than checking if readValue() returns empty string
• Use keyExists() to check if the entire key exists