Function fallback

fallback takes an array of Tasks and uses it as a fallback plan. For each value in the array, if it doesn't resolve to a successful value, the fallback plan will try the next.

This returns a Promise that resolves to the successful value or rejects with the final error in the plan.

Example

Using the fallback-plan, the code in the docs could be rewritten:

fallback([
   () => getRemoteResource('foo'),
   () => getRemoteResource('foo2'),
   () => getLocalResource('foo3'),
   () => getDefault()
]).then(useResource);

Actually, you could go a step further, since the call to getDefault has no parameters:

fallback([
   () => getRemoteResource('foo'),
   () => getRemoteResource('foo2'),
   () => getLocalResource('foo3'),
   getDefault
]).then(useResource);

since fallback handles:

• plain values
• Promises that resolve a value
• functions that return Promises
• functions that return a value