Add contract programming features to actions

[ioncreature]

I want it to be declarative as fuck, so why don't I implement contract-programming features for actions?

It could be schema arguments validation or even by function
And I want the same (schema/function validation) to self-check what have action returned

So design by contract usually describes 4 steps for functions: expect/require for args, and returns/ensure for result

Action({

    fn(deps) {
        return () => {}; // the action itself
    }

    expect: [ // json schema for each argument here (what to do with spread args?)
        {
            type: 'string',
            pattern: '^[0-9]{1,19}$'
        },
        {
            type: 'array'
            minItems: 1,
            items: [{
                type: 'string',
            }]
        }
    ],

    require(x, y) {
        // do some validation
    },

    returns: {} // json schema here too
    ensure() {} // function here
});