
Below are the list of differences between promise and observable,

| Observable | Promise |
| --- | --- |
| Declarative: Computation does not start until subscription so that they can be run whenever you need the result | Execute immediately on creation |
| Provide multiple values over time | Provide only one |
| Subscribe method is used for error handling which makes centralized and predictable error handling | Push errors to the child promises |
| Provides chaining and subscription to handle complex applications | Uses only .then() clause |

What is the difference between promise and observable?

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Observable	Promise
Declarative: Computation does not start until subscription so that they can be run whenever you need the result	Execute immediately on creation
Provide multiple values over time	Provide only one
Subscribe method is used for error handling which makes centralized and predictable error handling	Push errors to the child promises
Provides chaining and subscription to handle complex applications	Uses only .then() clause