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// @target: es6
// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc --target es6` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.
export enum PubSubRecordIsStoredInRedisAsA {
redisHash = "redisHash",
jsonEncodedRedisString = "jsonEncodedRedisString"
}
export interface PubSubRecord<NAME extends string, RECORD, IDENTIFIER extends Partial<RECORD>> {
name: NAME;
record: RECORD;
identifier: IDENTIFIER;
storedAs: PubSubRecordIsStoredInRedisAsA;
maxMsToWaitBeforePublishing: number;
}
type NameFieldConstructor<SO_FAR> =
SO_FAR extends {name: any} ? {} : {
name: <TYPE>(t?: TYPE) => BuildPubSubRecordType<SO_FAR & {name: TYPE}>
}
const buildNameFieldConstructor = <SO_FAR>(soFar: SO_FAR) => (
"name" in soFar ? {} : {
name: <TYPE>(instance: TYPE = undefined) =>
buildPubSubRecordType(Object.assign({}, soFar, {name: instance as TYPE}) as SO_FAR & {name: TYPE}) as BuildPubSubRecordType<SO_FAR & {name: TYPE}>
}
);
type StoredAsConstructor<SO_FAR> =
SO_FAR extends {storedAs: any} ? {} : {
storedAsJsonEncodedRedisString: () => BuildPubSubRecordType<SO_FAR & {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString}>;
storedRedisHash: () => BuildPubSubRecordType<SO_FAR & {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash}>;
}
const buildStoredAsConstructor = <SO_FAR>(soFar: SO_FAR) => (
"storedAs" in soFar ? {} : {
storedAsJsonEncodedRedisString: () =>
buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString})) as
BuildPubSubRecordType<SO_FAR & {storedAs: PubSubRecordIsStoredInRedisAsA.jsonEncodedRedisString}>,
storedAsRedisHash: () =>
buildPubSubRecordType(Object.assign({}, soFar, {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash})) as
BuildPubSubRecordType<SO_FAR & {storedAs: PubSubRecordIsStoredInRedisAsA.redisHash}>,
}
);
type IdentifierFieldConstructor<SO_FAR> =
SO_FAR extends {identifier: any} ? {} :
SO_FAR extends {record: any} ? {
identifier: <TYPE extends Partial<SO_FAR["record"]>>(t?: TYPE) => BuildPubSubRecordType<SO_FAR & {identifier: TYPE}>
} : {}
const buildIdentifierFieldConstructor = <SO_FAR>(soFar: SO_FAR) => (
"identifier" in soFar || (!("record" in soFar)) ? {} : {
identifier: <TYPE>(instance: TYPE = undefined) =>
buildPubSubRecordType(Object.assign({}, soFar, {identifier: instance as TYPE}) as SO_FAR & {identifier: TYPE}) as BuildPubSubRecordType<SO_FAR & {identifier: TYPE}>
}
);
type RecordFieldConstructor<SO_FAR> =
SO_FAR extends {record: any} ? {} : {
record: <TYPE>(t?: TYPE) => BuildPubSubRecordType<SO_FAR & {record: TYPE}>
}
const buildRecordFieldConstructor = <SO_FAR>(soFar: SO_FAR) => (
"record" in soFar ? {} : {
record: <TYPE>(instance: TYPE = undefined) =>
buildPubSubRecordType(Object.assign({}, soFar, {record: instance as TYPE}) as SO_FAR & {record: TYPE}) as BuildPubSubRecordType<SO_FAR & {record: TYPE}>
}
);
type MaxMsToWaitBeforePublishingFieldConstructor<SO_FAR> =
SO_FAR extends {maxMsToWaitBeforePublishing: any} ? {} : {
maxMsToWaitBeforePublishing: (t: number) => BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: number}>,
neverDelayPublishing: () => BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: 0}>,
}
const buildMaxMsToWaitBeforePublishingFieldConstructor = <SO_FAR>(soFar: SO_FAR): MaxMsToWaitBeforePublishingFieldConstructor<SO_FAR> => (
"maxMsToWaitBeforePublishing" in soFar ? {} : {
maxMsToWaitBeforePublishing: (instance: number = 0) =>
buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: instance})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: number}>,
neverDelayPublishing: () =>
buildPubSubRecordType(Object.assign({}, soFar, {maxMsToWaitBeforePublishing: 0})) as BuildPubSubRecordType<SO_FAR & {maxMsToWaitBeforePublishing: 0}>,
}
) as MaxMsToWaitBeforePublishingFieldConstructor<SO_FAR>;
type TypeConstructor<SO_FAR> =
SO_FAR extends {identifier: any, record: any, maxMsToWaitBeforePublishing: number, storedAs: PubSubRecordIsStoredInRedisAsA} ? {
type: SO_FAR,
fields: Set<keyof SO_FAR>,
hasField: (fieldName: string | number | symbol) => fieldName is keyof SO_FAR
} : {}
const buildType = <SO_FAR>(soFar: SO_FAR) => (
"identifier" in soFar && "object" in soFar && "maxMsToWaitBeforePublishing" in soFar && "PubSubRecordIsStoredInRedisAsA" in soFar ? {} : {
type: soFar,
fields: () => new Set(Object.keys(soFar) as (keyof SO_FAR)[]),
hasField: (fieldName: string | number | symbol) => fieldName in soFar
}
);
type BuildPubSubRecordType<SO_FAR> =
NameFieldConstructor<SO_FAR> &
IdentifierFieldConstructor<SO_FAR> &
RecordFieldConstructor<SO_FAR> &
StoredAsConstructor<SO_FAR> & // infinite loop goes away when you comment out this line
MaxMsToWaitBeforePublishingFieldConstructor<SO_FAR> &
TypeConstructor<SO_FAR>
const buildPubSubRecordType = <SO_FAR>(soFar: SO_FAR) => Object.assign(
{},
buildNameFieldConstructor(soFar),
buildIdentifierFieldConstructor(soFar),
buildRecordFieldConstructor(soFar),
buildStoredAsConstructor(soFar),
buildMaxMsToWaitBeforePublishingFieldConstructor(soFar),
buildType(soFar)
) as BuildPubSubRecordType<SO_FAR>;
const PubSubRecordType = buildPubSubRecordType({});
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