Set up V3 Typography component

.eslintrc

@@ -92,6 +92,13 @@
             {
                 "additionalHooks": "useIsomorphicLayoutEffect"
             }
+        ],
+        "@typescript-eslint/no-unused-vars": [
+            "error",
+            {
+                "argsIgnorePattern": "^_",
+                "varsIgnorePattern": "^_"
+            }
         ]
     }
 }

.storybook/preview.ts

@@ -39,6 +39,7 @@ const preview: Preview = {
                         "Typography",
                         "Animation",
                     ],
+                    "Core",
                     "General",
                     ["Animations", "Button", ["Base", "With Icon"], "*"],
                     "Form",

src/theme/typography/types.ts

@@ -7,6 +7,18 @@ export type TypographyCollectionMap = {
 
 export type TypographySetOptions = Partial<TypographySet>;
 
+export type TypographySizeType =
+    | "header-xxl"
+    | "header-xl"
+    | "header-lg"
+    | "header-md"
+    | "header-sm"
+    | "header-xs"
+    | "body-baseline"
+    | "body-lg"
+    | "body-md"
+    | "body-sm";
+
 export type TypographySet = {
     "header-xxl-light": CSSProp | string;
     "header-xxl-regular": CSSProp | string;

src/typography/helper.ts

@@ -0,0 +1,42 @@
+import { css } from "styled-components";
+import { Colour, Typography } from "../theme";
+import { TypographySizeType } from "../theme/typography/types";
+import { TypographyProps, TypographyWeight } from "./types";
+
+export const getTextStyle = (
+    type: TypographySizeType,
+    weight: TypographyWeight,
+    paragraph = false
+) => {
+    const token = `${type}-${weight.toLowerCase()}`;
+
+    return css`
+        ${Typography[token]}
+        ${paragraph ? "margin-bottom: 1.05em;" : "margin-bottom: 0;"}
+    `;
+};
+
+export const getDisplayStyle = (inline = false, paragraph = false) => {
+    if (paragraph) {
+        return css`
+            display: block;
+        `;
+    } else if (inline) {
+        return css`
+            display: inline;
+        `;
+    } else {
+        return css`
+            display: block;
+        `;
+    }
+};
+
+export const createTypographyStyles = (
+    textStyle: TypographySizeType,
+    props: TypographyProps
+) => css`
+    ${getTextStyle(textStyle, props.weight || "regular", props.paragraph)}
+    ${getDisplayStyle(props.inline, props.paragraph)}
+    color: ${Colour.text};
+`;

src/typography/index.ts

@@ -0,0 +1,2 @@
+export * from "./typography";
+export * from "./types";

src/typography/types.ts

@@ -0,0 +1,18 @@
+export type TypographyWeight = "regular" | "semibold" | "bold" | "light";
+
+export interface TypographyProps extends React.HTMLAttributes<HTMLElement> {
+    /** The font weight */
+    weight?: TypographyWeight | undefined;
+    /** Specifies if text is displayed inline */
+    inline?: boolean | undefined;
+    /** Specifies if text has a bottom margin */
+    paragraph?: boolean | undefined;
+}
+
+export interface TypographyLinkProps
+    extends React.AnchorHTMLAttributes<HTMLAnchorElement> {
+    /** The font weight */
+    weight?: TypographyWeight | undefined;
+    /** Displays indicator to signal that link leads to an external site */
+    external?: boolean | undefined;
+}

src/typography/typography.tsx

@@ -0,0 +1,88 @@
+import { ExternalIcon } from "@lifesg/react-icons/external";
+import styled, { css } from "styled-components";
+import { Colour } from "../theme";
+import { TypographySizeType } from "../theme/typography/types";
+import { createTypographyStyles, getTextStyle } from "./helper";
+import { TypographyLinkProps, TypographyProps } from "./types";
+
+export namespace Typography {
+    const createHeader = (
+        tag: keyof JSX.IntrinsicElements,
+        textStyle: TypographySizeType,
+        displayName: string
+    ) => {
+        const Header = styled(tag).attrs<TypographyProps>(({ inline }) => ({
+            as: inline ? "span" : undefined,
+        }))<TypographyProps>`
+            ${(props) => createTypographyStyles(textStyle, props)}
+        `;
+        Header.displayName = `Typography.${displayName}`;
+        return Header;
+    };
+
+    export const HeaderXXL = createHeader("h1", "header-xxl", "HeaderXXL");
+    export const HeaderXL = createHeader("h2", "header-xl", "HeaderXL");
+    export const HeaderLG = createHeader("h3", "header-lg", "HeaderLG");
+    export const HeaderMD = createHeader("h4", "header-md", "HeaderMD");
+    export const HeaderSM = createHeader("h5", "header-sm", "HeaderSM");
+    export const HeaderXS = createHeader("h6", "header-xs", "HeaderXS");
+
+    const createBody = (textStyle: TypographySizeType, displayName: string) => {
+        const Body = styled.p.attrs<TypographyProps>(({ inline }) => ({
+            as: inline ? "span" : undefined,
+        }))<TypographyProps>`
+            ${(props) => createTypographyStyles(textStyle, props)}
+        `;
+        Body.displayName = `Typography.${displayName}`;
+        return Body;
+    };
+
+    export const BodyBL = createBody("body-baseline", "BodyBL");
+    export const BodyLG = createBody("body-lg", "BodyLG");
+    export const BodyMD = createBody("body-md", "BodyMD");
+    export const BodySM = createBody("body-sm", "BodySM");
+
+    const createLinkComponent = (
+        textStyle: TypographySizeType,
+        displayName: string
+    ) => {
+        const HyperlinkBase = styled.a<TypographyLinkProps>`
+            ${(props) => css`
+                ${getTextStyle(textStyle, props.weight || "regular")}
+                color: ${Colour.hyperlink};
+                text-decoration: none;
+
+                :hover,
+                :active,
+                :focus {
+                    color: ${Colour["text-hover"]};
+                }
+            `}
+        `;
+
+        const Component = ({
+            external = false,
+            children,
+            ...rest
+        }: TypographyLinkProps) => (
+            <HyperlinkBase {...rest}>
+                {children}
+                {external && <StyledExternalIcon />}
+            </HyperlinkBase>
+        );
+        Component.displayName = `Typography.${displayName}`;
+        return Component;
+    };
+
+    export const LinkBL = createLinkComponent("body-baseline", "LinkBL");
+    export const LinkMD = createLinkComponent("body-md", "LinkMD");
+    export const LinkLG = createLinkComponent("body-lg", "LinkLG");
+    export const LinkSM = createLinkComponent("body-sm", "LinkSM");
+}
+
+const StyledExternalIcon = styled(ExternalIcon)`
+    height: 1lh;
+    width: 1em;
+    margin-left: 0.4em;
+    vertical-align: middle;
+`;

stories/storybook-common/api-table/index.ts

@@ -1,3 +1,4 @@
-export * from "./api-table-components";
 export * from "./api-table";
+export * from "./api-table-components";
 export * from "./markup-helpers";
+export * from "./types";

stories/typography/props-table.tsx

@@ -0,0 +1,100 @@
+import {
+    ApiTable,
+    ApiTableSectionProps,
+    TabAttribute,
+    Tabs,
+} from "../storybook-common";
+
+const TEXT_DATA: ApiTableSectionProps[] = [
+    {
+        attributes: [
+            {
+                name: "",
+                description: (
+                    <>
+                        This component also inherits props from{" "}
+                        <a
+                            href="https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement"
+                            target="_blank"
+                            rel="noreferrer"
+                        >
+                            HTMLElement
+                        </a>
+                    </>
+                ),
+            },
+            {
+                name: "inline",
+                description:
+                    "Sets the text to an inline display to allow a combination of text in a single line",
+                propTypes: ["boolean"],
+            },
+            {
+                name: "maxLines",
+                description:
+                    "Specifies the number of lines visible. Additional lines will be truncated",
+                propTypes: ["number"],
+            },
+            {
+                name: "paragraph",
+                description:
+                    "Adds an extra bottom margin to allow a better separation of text blocks",
+                propTypes: ["boolean"],
+                defaultValue: "false",
+            },
+            {
+                name: "weight",
+                description: "The weight of the text component",
+                propTypes: [`"regular"`, `"semibold"`, `"bold"`, `"light"`],
+                defaultValue: `"regular"`,
+            },
+        ],
+    },
+];
+
+const LINK_DATA: ApiTableSectionProps[] = [
+    {
+        attributes: [
+            {
+                name: "",
+                description: (
+                    <>
+                        This component also inherits props from{" "}
+                        <a
+                            href="https://developer.mozilla.org/en-US/docs/Web/API/HTMLAnchorElement"
+                            target="_blank"
+                            rel="noreferrer"
+                        >
+                            HTMLAnchorElement
+                        </a>
+                    </>
+                ),
+            },
+            {
+                name: "weight",
+                description: "The weight of the hyperlink component",
+                propTypes: [`"regular"`, `"semibold"`, `"bold"`, `"light"`],
+                defaultValue: `"regular"`,
+            },
+            {
+                name: "external",
+                description:
+                    "Indicates if the link is external to the domain. Adds an indicator at the end of the link",
+                propTypes: ["boolean"],
+            },
+        ],
+    },
+];
+
+const PROPS_TABLE_DATA: TabAttribute[] = [
+    {
+        title: "Header/Body",
+        component: <ApiTable sections={TEXT_DATA} />,
+    },
+    {
+        title: "Link",
+        component: <ApiTable sections={LINK_DATA} />,
+    },
+];
+
+export const PropsTable = () => <Tabs tabs={PROPS_TABLE_DATA} />;

stories/typography/typography.mdx

@@ -0,0 +1,80 @@
+import { Canvas, Meta } from "@storybook/blocks";
+import { DocInfo } from "stories/storybook-common";
+import { PropsTable } from "./props-table";
+import * as TypographyStories from "./typography.stories";
+
+<Meta of={TypographyStories} />
+
+# Typography
+
+## Overview
+
+The component that is used for headings, body text, links and more.
+
+```tsx
+import { Typography } from "@lifesg/react-design-system/typography";
+```
+
+<Canvas of={TypographyStories.TypographySet} />
+
+<DocInfo>
+**Which module to use?**<br /><br />
+
+**Scenario 1: Text content**
+
+If you are rendering text content, such as headings, paragraphs and links, use
+this Typography component as it comes with additional capabilities to help you
+lay out text.<br /><br />
+
+**Scenario 2: Parent container**
+
+If you are rendering a container that contains text children but does not need
+to be a text element itself, apply the [typography design
+tokens](/docs/foundations-typography-introduction--docs) directly.<br /><br />
+
+**Scenario 3: HTML children**
+
+If you are rendering a container that can contain arbitrary HTML markup, use the
+[Markup component](/docs/general-markup--docs).
+
+</DocInfo>
+
+## Combining styles
+
+### Inline text
+
+You can nest text within text using the `inline` prop. The nested text is
+rendered as a `span` element.
+
+<Canvas of={TypographyStories.InlineText} />
+
+### Inline link
+
+You can include links within a set of text. Links are inline by default.
+
+<Canvas of={TypographyStories.InlineLink} />
+
+### Font weight
+
+You can include different weights within a set of text using the `weight` and
+`inline` props.
+
+<Canvas of={TypographyStories.MixedFontWeights} />
+
+## Paragraph specification
+
+You can include paragraph spacing between text blocks by specifying the
+`paragraph` prop.
+
+<Canvas of={TypographyStories.Paragraphs} />
+
+## External links
+
+If a link leads to an external site, it is recommended to specify the `external`
+prop, which displays an indicator.
+
+<Canvas of={TypographyStories.ExternalLink} />
+
+## Component API
+
+<PropsTable />