Evaluating flags

The Variation method determines whether a flag is enabled or not for a specific context. In the client-side .NET SDK, there is a variation method for each type, such as BoolVariation or StringVariation.

variation calls take the feature flag key and a fallback value.

Here is an example:

client.BoolVariation("flag-key-123abc", false);
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines whether or not a flag is enabled for a specific context. variation calls take the feature flag key and a fallback value. When LDClient is initialized for the first time at app launch, contexts receive the feature flag fallback values until an initial connection to LaunchDarkly completes.

In Android, there is a variation method for each type, such as boolVariation or stringVariation.

Here is an example:

boolean variationResult = client.boolVariation(flagKey, false);
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation methods determine whether or not a flag is enabled for a specific context. The variation method signatures take the feature flag key and a fallback value. When the client is initialized for the first time, contexts receive the feature flag fallback values until an initial connection to LaunchDarkly completes.

There are variation methods for each type, such as BoolVariation or StringVariation.

Here is an example:

bool show_feature = client.BoolVariation("flag-key-123abc", false);
if (show_feature) {
    // Application code to show the feature
} else {
    // The code to run if the feature is off
}
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

To learn more, read the Client documentation.

To evaluate any feature flag for the current user, call variation:

const flagValue = client.variation('flag-key-123abc', false);
// proceed based on flag value, for example:
if (flagValue)  {
  // feature flag targeting is on
} else {
  // feature flag targeting is off
}
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You must provide all relevant user attributes for each evaluation for your targeting rules to apply correctly.

The return value of variation is always either one of the variations you defined for your flag in the flag's Targeting tab, or the fallback value. The fallback value is the second parameter to variation.

You can also fetch all flags for the current user.

Here is an example:

const flags = client.allFlags();
const flagValue = flags['flag-key-123abc'];
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This returns a key-value map of all your feature flags. It contains null values for any flags that could not be evaluated.

Both of these methods are synchronous. The client always has the last known flag values in memory, so retrieving them does not involve any input/output (I/O).

The variation methods determine the flag value for the current context. variation calls take the feature flag key and a fallback value. When LDClient is initialized for the first time at app launch, end users receive the feature flag fallback values until an initial connection to LaunchDarkly completes.

In Flutter, there is a variation method for each type, such as boolVariation or stringVariation.

Here is an example:

bool variationResult = await LDClient.boolVariation(flagKey, false);
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation functions determine the flag value for the current context. Variation functions take the feature flag key and a fallback value as parameters. If the flag does not exist, cannot be cast to the correct return type, or the LDClient is not started, the function returns the fallback value.

In the iOS SDK, there is a variation method for each type, such as boolVariation or jsonVariation.

Here is an example:

let boolFlagValue = LDClient.get()!.boolVariation(forKey: "bool-flag-key-123abc", defaultValue: false)
let jsonFlagValue = LDClient.get()!.jsonVariation(forKey: "json-flag-key-456def", defaultValue: ["enabled": false, "special": "none"])
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives. variation calls take the feature flag key and a fallback value.

Here is an example of the variation method:

client.variation('flag-key-123abc', false);
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a user receives. variation calls take the feature flag key and a fallback value.

Here is an example:

const value = client.variation('flag-key-123abc', false);
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You must provide all relevant user attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines whether a flag is enabled or not for a specific context. In React Native, there is a variation method for each type, such as boolVariation or stringVariation.

Variation calls take the feature flag key and a fallback value. When LDClient is initialized for the first time at app launch, end users receive feature flag fallback values until an initial connection to LaunchDarkly is completed.

Here is an example:

let boolResult = await client.boolVariation('bool-flag-key-123abc', false);
let numResult = await client.numberVariation('numeric-flag-key-123abc', 2);
let stringResult = await client.stringVariation('string-flag-key-123abc', '');
let jsonResult = await client.jsonVariation('json-flag-key-123abc', {});
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The *variation methods determine which variation of a feature flag a context receives. *variation calls take a feature flag key and a fallback value.

Here is an example:

REM typed variations
myInt = launchDarkly.intVariation("flag-key-123abc", 123)
myBool = launchDarkly.boolVariation("flag-key-123abc", false)
myString = launchDarkly.stringVariation("flag-key-123abc", "hello world!")
myObjectOrArray = launchDarkly.jsonVariation("flag-key-123abc", {"value": 123})
REM generic variation
myValue = launchDarkly.variation("flag-key-123abc", false)
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The Variation methods determine whether a flag is enabled or not for a specific context. In .NET, there is a Variation method for each type:

• BoolVariation
• DoubleVariation
• FloatVariation
• IntVariation
• JsonVariation
• StringVariation.

Variation calls take the feature flag key, a Context, and a fallback value.

Here is an example:

var value = client.BoolVariation("your.feature.key", context, false);
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation family of methods determine the flag value for a specific user. In Apex, there is a variation method for each type, such as boolVariation or stringVariation. The functions take an LDUser, feature flag key, and a fallback value.

Here is an example:

Boolean value = client.boolVariation(user, 'your.feature.key', false);
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You must provide all relevant user attributes for each evaluation for your targeting rules to apply correctly.

The variation family of functions determine whether a flag is enabled or not for a specific user. In C, there is a variation function for each type, such as LDBoolVariation or LDStringVariation.

The functions take an LDClient, LDUser, feature flag key, fallback value, and optional LDDetails struct for an evaluation explanation.

Here is an example:

bool value = LDBoolVariation(client, user, "your.feature.key", false, NULL);
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You must provide all relevant user attributes for each evaluation for your targeting rules to apply correctly.

The variation function determines whether a flag is enabled or not for a specific context. The functions take a flag key, context, fallback value, and an instance tag. In the example below, the fallback value is false. The instance tag is optional.

Flag = ldclient:variation(<<"flag-key-123abc">>, #{key => <<"context-key-123abc">>,}, false, your_instance)
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The Variation methods determine whether a flag is enabled or not for a specific context. In Go, there is a Variation method for each type:

• BoolVariation
• IntVariation
• Float64Variation
• StringVariation
• JSONVariation, which can be any JSON type.

Variation methods take the feature flag key, a context, and a fallback value. In the example below, the fallback value is false.

The Variation call generates analytics events to tell LaunchDarkly about the flag evaluation and the context attributes, so the context will be added to the Contexts list if a context with that key doesn't exist already.

Here is an example:

result, _ := client.BoolVariation("your.feature.key", context, false)
// result is now true or false depending on the setting of this boolean feature flag
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation family of functions determine whether a flag is enabled or not for a specific context. In Haskell, there is a variation function for each type:

• boolVariation
• intVariation
• doubleVariation
• stringVariation
• jsonVariation

The functions take a Client, Context, feature flag key, and a fallback value. In the example below, the fallback value is False.

Here is an example:

myBoolVariation <- boolVariation client "flag-key-123abc" context False
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation methods determine which variation of a feature flag a context receives.

In Java, there is a variation method for each type:

• boolVariation
• intVariation
• doubleVariation
• stringVariation
• jsonValueVariation, which can be of any JSON type.

The variation methods take the feature flag key, an LDContext, and a fallback value.

Here is an example:

boolean value = client.boolVariation("flag-key-123abc", context, false);
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation family of functions determine whether a flag is enabled or not for a specific user. In Lua, there is a variation function for each type, such as boolVariation or stringVariation.

To learn more about configuration options, read the API docs.

Here is an example:

local value = client:boolVariation(user, "flag-key-123abc", false)
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You must provide all relevant user attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives.

variation calls take the feature flag key, an LDContext, and a fallback value.

Here is an example:

client.variation('flag-key-123abc', context, false,
  (err, value) => {
    // check value and proceed accordingly
  });
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You must provide all relevant attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives. variation calls take the feature flag key, an LDContext, and a fallback value.

Here is an example:

$value = $client->variation($key, $context, false);
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You must provide all relevant attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives. variation calls take the feature flag key, a Context, and a fallback value.

Here is an example:

show_feature = ldclient.get().variation("your.feature.key", context, False)
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives.

variation calls take the feature flag key, an LDContext or user hash, and a fallback value. To learn more about constructing the context or user hash, read User and context configuration.

Here is an example:

value = client.variation("your.feature.key", context, false)
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You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation methods determine whether a flag is enabled or not for a specific user. In Rust, there is a variation method for each type:

• bool_variation,
• int_variation,
• float_variation,
• str_variation for strings, and
• json_variation, which can be any JSON type.

variation methods take a Context, the feature flag key, and a fallback value. In the example below, the fallback value is false.

Here is an example:

let result = client.bool_variation(&context, "your.feature.key", false);
// result is now true or false depending on the setting of this boolean feature flag
COPY

You must provide all relevant context attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives. variation calls take the feature flag key, an LDContext, and a default value.

Here is an example:

const flagValue = await client.variation('flag-key-123abc', context, false);
COPY

You must provide all relevant attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives. variation calls take the feature flag key, an LDContext, and a default value.

Here is an example:

const flagValue = await client.variation('flag-key-123abc', context, false);
COPY

You must provide all relevant attributes for each evaluation for your targeting rules to apply correctly.

The variation method determines which variation of a feature flag a context receives. variation calls take the feature flag key, an LDContext, and a fallback value.

Here is an example:

const flagValue = await client.variation('flag-key-123abc', context, false);
COPY

You must provide all relevant attributes for each evaluation for your targeting rules to apply correctly.