where("period @> date ? ", shares_at)

a tuple { selector, private key, public key } is created

A record can be viewed as the computer analog of a mathematical tuple, although a tuple may or may not be considered a record, and vice versa, depending on conventions and the specific programming language.

An object in object-oriented language is essentially a record that contains procedures specialized to handle that record; and object types are an elaboration of record types. Indeed, in most object-oriented languages, records are just special cases of objects, and are known as plain old data structures (PODSs), to contrast with objects that use OO features.

A record type is a data type that describes such values and variables.

In type theory, product types (with no field names) are generally preferred due to their simplicity

Most typed functional programming languages implement tuples directly as product types

Modules do not add anything to the global (window) scope. Modules always are in strict mode. Loading the same module twice in the same file will have no effect, as modules are only executed once. Modules require a server environment.

Emphasizing lifetime-polymorphism can also make type inference untenable, a design choice that wouldn’t fit OCaml.

PDU Session types are defined: IPv4, IPv6, IPv4v6, Ethernet, Unstructured.

[Episode!]! represents an array of Episode objects. Since it is also non-nullable, you can always expect an array (with zero or more items) when you query the appearsIn field. And since Episode! is also non-nullable, you can always expect every item of the array to be an Episode object.

If you want a workaround for the case where you can't just replace key with a string literal, you could write your own user-defined type guard function called hasProp(obj, prop). The implementation would just return prop in obj, but its type signature explicitly says that a true result should cause obj to be narrowed to just those union members with a key of type prop: function hasProp<T extends object, K extends PropertyKey>( obj: T, prop: K ): obj is Extract<T, { [P in K]?: any }> { return prop in obj; } and then in your function, replace key in a with hasProp(a, key): function f3(a: A) { const key = 'b'; if (hasProp(a, key)) { return a[key]; // okay } return 42; }

Type switches

为什么JavaScript里面typeof(null)的值是"object"？

in this moment Chris and the deer have their owncoagulation: fusing into one “buck” (and obviously Peele was playing uponthis terminology associated with the Black male slave), they jointly chargeand kill their enemy. Together, the “vermin” strike back

Chris makes use of thedead deer; another (more mystical) analysis could posit that the deer takesrevenge on the hunter, using Chris’s body as a vehicle

First, the conflation of the deerwith the devaluation of Black life nods to the long-standing tradition of usinganimals to speak back to the power structures upheld by plantation slaveryin the form of animal folktales. And second, this deer comes roaring back tolife. He gets his revenge on the family that made his noble head into a trophy.The taxidermied deer is a speaking animal that has a kind of second life, andthere are multiple ways we might read its importance in Chris’s escape

the deer strikes back

Like the trickster tales discussed above, the films we are lookingat here do not make animals the focal point, but use them as a means of“thinking with” humans.

The trickster is an animal low on the peckingorder (like a rabbit) who finds himself in a jam and must use his wits, charms,and other skill sets to outfox his more powerful enemies. He is an animalsurrogate that speaks softly of strategies for resistance

Wagner emphasizes thatsuch animal tales often provided coded ways of imparting strategies forresistance and that this story has historical connections not only to the tropeof the speaking animal from African trickster mythologies like the spiderAnansi, but also perhaps, to Aesop’s animal fable

educe animals to mere metaphors, similes, or symbolsdo not seem promising for theorizing ethical recognition of actual animals.Donna Haraway, for example, criticizes philosophical texts that show a “pro-found absence of curiosity about or respect for and with actual animals,even as innumerable references to diverse animals are invoked.” 15 SusanMcHugh, meanwhile, suggests that “the aesthetic structures of metaphor,though precariously supporting the human subject, seem unable to bearanimal agency.”16 An

She maybelieve the comparison reveals the moral horror of industrial animal agri-culture, but, as Bénédicte Boisseron argues, such comparisons “instrumen-talize” Blackness in a “self-serving” way, ignoring the complex and ongoingBlack struggle against dehumanizing discourses and institutions in order toframe “the animal” as “the new black.

remind us of the historical reduction of the human to the status of ananimal under transatlantic slavery, but also were used as a mode of resistancefor enslaved peoples

Rather than viewing fables as operating with a purely substitutivelogic, where the animal stands in for the human, recent criticism explores thepossibility that the fable can imagine relationality and even allyship amongspecies

lens of alliance, not solely analogy

Rather, the appearance of animals in some recentfilms highlights the unequal treatment of Black lives in America in a mannerthat continues the fable tradition, and simultaneously emphasizes the human

Theseworks encode various strategies of survival in an era in which Black livescontinue to be devalued

Any resistance must be sanitized soas to be tolerable” for the general audience. 5 But resistance also works not bybeing sanitized, but by being hidden in plain sight, coded as symbols legibleto some but not to all. The use of animal fables has a long-standing historydating back to slavery as providing such a coded language of resistance

Wagner notes that theweaker animals use their wits as a means of overcoming the unequal powerdistribution in the world they navigated

he “speaking animal,” which acknowledgesthe dialectic capacity of the symbolic animal of fables to stage a conversationabout subjugation and resistance, but simultaneously, to point beyond itselfto the reality of animal life.

Paraphrasing Joel Chandler Harris, BryanWagner writes that animal stories were “political allegories in which therelative position of the weaker animals corresponded to the global per-spective of the race.”

interval values can be written using the following verbose syntax: [@] quantity unit [quantity unit...] [direction] where quantity is a number (possibly signed); unit is microsecond, millisecond, second, minute, hour, day, week, month, year, decade, century, millennium, or abbreviations or plurals of these units

daterange — Range of date, datemultirange — corresponding Multirange

My freely downloadable Beginning Mathematical Logic is a Study Guide, suggesting introductory readings beginning at sub-Masters level. Take a look at the main introductory suggestions on First-Order Logic, Computability, Set Theory as useful preparation. Tackling mid-level books will help develop your appreciation of mathematical approaches to logic.

by using symbols as keys, you will be able to use the implicit conversion of a Mash via the #to_hash method to destructure (or splat) the contents of a Mash out to a block

Hashie does not have built-in support for coercing boolean values, since Ruby does not have a built-in boolean type or standard method for coercing to a boolean. You can coerce to booleans using a custom proc.

A File object is a specific kind of Blob, and can be used in any context that a Blob can.

specific types of diagrams are also called a type of flow diagrams

disport itself happily in its new and extended Quadrivium withoutpassing through the Trivium. But the scholastic tradition, though broken andmaimed, still lingered in the public schools and universities:

get usually

a hyponym is in a type-of relationship with its hypernym

particular

supports

susbtantial

This collection of three classes of fields

researcher

But in GraphQL, all types are nullable by default, and you opt into non-nullability

In other typed languages, like TypeScript, Flow, Rust, or Haskell, all types are non-nullable by default, and you opt into nullability.

DICER1 syndrome is a rare genetic condition predisposing to hereditary cancer and caused by variants in the DICER1

DICER1 syndrome is an autosomal-dominant,pleiotropic, tumor-predisposition disorder arisingfrom pathogenic germline variants in DICER1, whichencodes an endoribonuclease integral to processingmicroRNAs

As we all experience the world differently, the way of learning each of us is diverse. Comprehending how we learn things would help the teachers to understand their students and they don’t have to see any students lagging. Every kid doesn’t come first in the class. It is not because they have a smaller brain size. It is because their brain would acknowledge a different procedure of learning. In this article we are going to discuss the 4 types of learning styles so that you can understand – what type of learner are you?

There are project layouts that put implementation files and test files together.

type

Gutenberg used his second edition of the Catholicon to experiment with casting type not letter by letter but in two- line slugs that could be reused in later printings, saving the labor of distributing then resetting the type letter by letter.

assumes that the function identifier f has a particular type

we often work hard to make symbols and strings interchangeable in contexts where it makes sense

Similar to the idea of {{ if .Title }}, does Micro.blog (or Hugo) have a way to identify if a post only contains images and capture that to a variable?

Over these two centuries, an in-creasing impatience for the ancient art of memory based on the use of imagi-nation could be detected in the academic milieu.

All this bears little resemblance to modern literary ideals, in which the author is constructed somewhat heroically as an individual creative source.

Behind this order of paper slips that guarantees mobility and rearrange-ment, one can recognize the same economy of signs that a century earlier contributes to a major paradigmatic shift. Johannes Gutenberg ’ s invention of the printing press not only forges most obviously associations of typeset-ting, steel models, pouring mechanisms for individual letter types, special alloys, and composing sticks for setting lines of type. 28

the name union comes from type theory. The union number | string is composed by taking the union of the values from each type. Notice that given two sets with corresponding facts about each set, only the intersection of those facts applies to the union of the sets themselves.

For example, if we had a room of tall people wearing hats, and another room of Spanish speakers wearing hats, after combining those rooms, the only thing we know about every person is that they must be wearing a hat.

Type aliases and interfaces are very similar, and in many cases you can choose between them freely. Almost all features of an interface are available in type, the key distinction is that a type cannot be re-opened to add new properties vs an interface which is always extendable.

Regarding mapped types, remember that { [K in T]: U } is a special form - it can't be combined with other properties within the { }. So there's not really a name for the [K in T: U] part because it's just part of the overall "mapped type" syntax { [K in T]: U }

Which... is confusing because Palette technically does have an index signature Palette is a mapped type, and mapped types don't have index signatures. The fact that both use [ ] is a syntactic coincidence.

// Second case (unexpected) interface C { [x:string]: number } interface D { x: number } const d: D = { x: 1 }; const c: C = d; // error // Type 'D' is not assignable to type 'C'. // Index signature is missing in type 'D'.

So now the question is, why does Session, an interface, not get implicit index signatures while SessionType, an identically-structured typealias, *does*? Surely, you might again think, the compiler does not simply deny implicit index signatures tointerface` types? Surprisingly enough, this is exactly what happens. See microsoft/TypeScript#15300, specifically this comment: Just to fill people in, this behavior is currently by design. Because interfaces can be augmented by additional declarations but type aliases can't, it's "safer" (heavy quotes on that one) to infer an implicit index signature for type aliases than for interfaces. But we'll consider doing it for interfaces as well if that seems to make sense And there you go. You cannot use a Session in place of a WithAdditionalParams<Session> because it's possible that someone might merge properties that conflict with the index signature at some later date. Whether or not that is a compelling reason is up for rather vigorous debate, as you can see if you read through microsoft/TypeScript#15300.

The type-fest package contains only types, meaning they are only used at compile-time and nothing is ever compiled into actual JavaScript code. This package contains functions that are compiled into JavaScript code and used at runtime.

Type Brigade is Vancouver’s type meetup.

allows

This isn't too restrictive, and provides a nice type type guard.

the tuple() function you need can be succinctly written as: export type Lit = string | number | boolean | undefined | null | void | {}; export const tuple = <T extends Lit[]>(...args: T) => args;

const list = ['a', 'b', 'c'] as const; // TS3.4 syntax type NeededUnionType = typeof list[number]; // 'a'|'b'|'c';

possible to tell the compiler to infer the type of a tuple of literals as a tuple of literals, instead of as, say, string[], by using the as const syntax.

Or, maybe better, interpret the list as a tuple type: const list: ['a','b','c'] = ['a','b','c']; // tuple

One problem is the literal ['a','b','c'] will be inferred as type string[], so the type system will forget about the specific values.

function strictIsDog<T extends Dog extends T ? unknown : never>( // like <T super Dog> candidate: Dog | T // if Dog extends T then Dog | T is T ): candidate is Dog { // compiler recognizes that Dog | T can narrow to T return "bark" in candidate; } if (strictIsDog(animal)) {} // okay if (strictIsDog(dog)) {} // okay if (strictIsDog(mixed)) {} // okay if (strictIsDog(cat)) {} // error! // ~~~ <-- Cat is not assignable to Dog

* Now it's correct within the laws of the type system, but makes zero practical sense, * because there exists no runtime representation of the type `Date & string`. * * The type system doesn't care whether a type can be represented in runtime though.

Using the second type guard forces the user to write a more precise type and therefore manifest any nonsensical type guards that produce never, like: function silly<T extends number>(candidate: T): candidate is T & boolean { … }

The best way to do this is to derive the type Format from a value like an array which contains all of the Format literals.

So is @Ryan Cavanaugh's answer the only viable solution? It seems extremely verbose...

My question is specifically if there is a way to do user defined type guards using the type itself

function isKeyOfMcuParams(x: string): x is keyof McuParams { switch (x) { case 'foo': case 'bar': case 'baz': return true; default: return false; } }

Is it possible to write a user defined type guard for a keyof string type such as keyOf foo when foo is defined ONLY as a type (and not in an array)?

It means that when having a type guard:TypeScript and JavaScript runtime are tied to the same behaviour.

Inside the if statement, TypeScript will assume that amount cannot be anything else than a string, which is true also at the runtime thanks to typeof JavaScript operator.

This “gap” between what we call “runtime” and “static analysis” can be filled using TypeScript Type Guards.

we use a type guard here to say that, if this function returns true, any further usage of key will be of the specified type. Otherwise, it's still just a string.

function hasKey<O>(obj: O, key: PropertyKey): key is keyof O { return key in obj }

Adding to the accepted answer, if you happen to need to use a type guard against a mixin, you'll get this error too, since the is operator doesn't behave as an implements would.

Regarding the error message, the predicate type must be assignable to the value type because the type guard is used to check whether a value with a less-specific type is in fact a value with a more-specific type. For example, consider this guard: function isApe(value: Animal): value is Ape { return /* ... */ } Ape is assignable to Animal, but not vice versa.

If there is no relationship between the value's type and the type in the type predicate, the guard would make no sense. For example, TypeScript won't allow a user-defined guard like this: function isString(value: Date): value is string { return typeof value === "string"; }

const isValidMethodForHandler = <T extends { [i: string]: any }>(handler: T) => ( method: string ): method is Extract<keyof T, string> => Object.keys(handler).indexOf(method) !== -1;

Type Annotations:These annotations can be applied to any place where a type is being used. For example, we can annotate the return type of a method.

We can also define these properties for data types that we do not control, for example providing a custom way of hashing a data type implemented by someone else

Moss points out the implied analogy between the commonplace-book and "moveable type, capable of both setting a page of text in an apparentiy immutable form and of rearranging all the eléments of that page into other pattems for other meanings" (p. 252); with characteristie prudence, she mentions this analogy only when it finally becomes explicit in one of her later texts, Jean Oudart's Methode des orateurs oí 1668

We added the X-Content-Type-Options: nosniff header to our raw URL responses way back in 2011 as a first step in combating hotlinking. This has the effect of forcing the browser to treat content in accordance with the Content-Type header. That means that when we set Content-Type: text/plain for raw views of files, the browser will refuse to treat that file as JavaScript or CSS.