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don't use errors as control flow
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@alexcjohnson
alexcjohnson committed Apr 28, 2020
1 parent 4cdb7b0 commit b44bd54
Showing 1 changed file with 72 additions and 72 deletions.
144 changes: 72 additions & 72 deletions dash-renderer/src/actions/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -136,48 +136,44 @@ function moveHistory(changeType) {
}

function unwrapIfNotMulti(paths, idProps, spec, anyVals, depType) {
let msg = '';

if (isMultiValued(spec)) {
return idProps;
return [idProps, msg];
}

if (idProps.length !== 1) {
if (!idProps.length) {
if (typeof spec.id === 'string') {
throw new ReferenceError(
'A nonexistent object was used in an `' +
depType +
'` of a Dash callback. The id of this object is `' +
spec.id +
'` and the property is `' +
spec.property +
'`. The string ids in the current layout are: [' +
keys(paths.strs).join(', ') +
']'
);
}
throw new ReferenceError(
const isStr = typeof spec.id === 'string';
msg =
'A nonexistent object was used in an `' +
depType +
'` of a Dash callback. The id of this object is ' +
JSON.stringify(spec.id) +
(anyVals ? ' with MATCH values ' + anyVals : '') +
' and the property is `' +
spec.property +
'`. The wildcard ids currently available are logged above.'
);
}
throw new ReferenceError(
'Multiple objects were found for an `' +
depType +
'` of a Dash callback. The id of this object is ' +
(isStr
? '`' + spec.id + '`'
: JSON.stringify(spec.id) +
(anyVals ? ' with MATCH values ' + anyVals : '')) +
' and the property is `' +
spec.property +
(isStr
? '`. The string ids in the current layout are: [' +
keys(paths.strs).join(', ') +
']'
: '`. The wildcard ids currently available are logged above.');
} else {
msg =
'Multiple objects were found for an `' +
depType +
'` of a callback that only takes one value. The id spec is ' +
JSON.stringify(spec.id) +
(anyVals ? ' with MATCH values ' + anyVals : '') +
' and the property is `' +
spec.property +
'`. The objects we found are: ' +
JSON.stringify(map(pick(['id', 'property']), idProps))
);
JSON.stringify(map(pick(['id', 'property']), idProps));
}
}
return idProps[0];
return [idProps[0], msg];
}

function startCallbacks(callbacks) {
Expand Down Expand Up @@ -259,26 +255,30 @@ async function fireReadyCallbacks(dispatch, getState, callbacks) {
return preventCallback();
}

let outputs;
try {
outputs = allOutputs.map((out, i) =>
unwrapIfNotMulti(
paths,
map(pick(['id', 'property']), out),
cb.callback.outputs[i],
cb.anyVals,
'Output'
)
const outputs = [];
const outputErrors = [];
allOutputs.forEach((out, i) => {
const [outi, erri] = unwrapIfNotMulti(
paths,
map(pick(['id', 'property']), out),
cb.callback.outputs[i],
cb.anyVals,
'Output'
);
} catch (e) {
if (e instanceof ReferenceError && !flatten(inVals).length) {
// This case is all-empty multivalued wildcard inputs,
// which we would normally fire the callback for, except
// some outputs are missing. So instead we treat it like
// regular missing inputs and just silently prevent it.
return preventCallback();
outputs.push(outi);
if (erri) {
outputErrors.push(erri);
}
throw e;
});
if (outputErrors.length) {
if (flatten(inVals).length) {
refErr(outputErrors, paths);
}
// This case is all-empty multivalued wildcard inputs,
// which we would normally fire the callback for, except
// some outputs are missing. So instead we treat it like
// regular missing inputs and just silently prevent it.
return preventCallback();
}

payload = {
Expand Down Expand Up @@ -431,8 +431,8 @@ function fillVals(paths, layout, cb, specs, depType, allowAllMissing) {
const errors = [];
let emptyMultiValues = 0;

const fillInputs = (inputList, i) =>
unwrapIfNotMulti(
const inputVals = getter(paths).map((inputList, i) => {
const [inputs, inputError] = unwrapIfNotMulti(
paths,
inputList.map(({id, property, path: path_}) => ({
id,
Expand All @@ -443,44 +443,44 @@ function fillVals(paths, layout, cb, specs, depType, allowAllMissing) {
cb.anyVals,
depType
);

const tryFill = (inputList, i) => {
try {
const inputs = fillInputs(inputList, i);
if (isMultiValued(specs[i]) && !inputs.length) {
emptyMultiValues++;
}
return inputs;
} catch (e) {
if (e instanceof ReferenceError) {
errors.push(e);
return null;
}
// any other error we still want to see!
throw e;
if (isMultiValued(specs[i]) && !inputs.length) {
emptyMultiValues++;
}
};

const inputVals = getter(paths).map(allowAllMissing ? tryFill : fillInputs);
if (inputError) {
errors.push(inputError);
}
return inputs;
});

if (errors.length) {
if (errors.length + emptyMultiValues === inputVals.length) {
if (
allowAllMissing &&
errors.length + emptyMultiValues === inputVals.length
) {
// We have at least one non-multivalued input, but all simple and
// multi-valued inputs are missing.
// (if all inputs are multivalued and all missing we still return
// them as normal, and fire the callback.)
return null;
}
// If we get here we have some missing and some present inputs.
// That's a real error, so rethrow the first missing error.
// Or all missing in a context that doesn't allow this.
// That's a real problem, so throw the first message as an error.
refErr(errors, paths);
}

return inputVals;
}

function refErr(errors, paths) {
const err = errors[0];
if (err.indexOf('logged above') !== -1) {
// Wildcard reference errors mention a list of wildcard specs logged
// TODO: unwrapped list of wildcard ids?
// eslint-disable-next-line no-console
console.error(paths.objs);
throw errors[0];
}

return inputVals;
throw new ReferenceError(err);
}

function handleServerside(config, payload, hooks) {
Expand Down

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