next.js/packages/font/src/local/loader.test.ts

import nextFontLocalFontLoader from './loader'

describe('next/font/local loader', () => {
  describe('generated CSS', () => {
    test('Default CSS', async () => {
      const { css } = await nextFontLocalFontLoader({
        functionName: '',
        data: [{ src: './my-font.woff2' }],
        emitFontFile: () => '/_next/static/media/my-font.woff2',
        resolve: jest.fn(),
        isDev: false,
        isServer: true,
        variableName: 'myFont',
        loaderContext: {
          fs: {
            readFile: (_: string, cb: any) => cb(null, 'fontdata'),
          },
        } as any,
      })

      expect(css).toMatchInlineSnapshot(`
        "@font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        }
        "
      `)
    })

    test('Weight and style', async () => {
      const { css } = await nextFontLocalFontLoader({
        functionName: '',
        data: [{ src: './my-font.woff2', weight: '100 900', style: 'italic' }],
        emitFontFile: () => '/_next/static/media/my-font.woff2',
        resolve: jest.fn(),
        isDev: false,
        isServer: true,
        variableName: 'myFont',
        loaderContext: {
          fs: {
            readFile: (_: string, cb: any) => cb(null, 'fontdata'),
          },
        } as any,
      })

      expect(css).toMatchInlineSnapshot(`
        "@font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 100 900;
        font-style: italic;
        }
        "
      `)
    })

    test('Other properties', async () => {
      const { css } = await nextFontLocalFontLoader({
        functionName: '',
        data: [
          {
            src: './my-font.woff2',
            declarations: [
              { prop: 'font-feature-settings', value: '"smcp" on' },
              { prop: 'ascent-override', value: '90%' },
            ],
          },
        ],
        emitFontFile: () => '/_next/static/media/my-font.woff2',
        resolve: jest.fn(),
        isDev: false,
        isServer: true,
        variableName: 'myFont',
        loaderContext: {
          fs: {
            readFile: (_: string, cb: any) => cb(null, 'fontdata'),
          },
        } as any,
      })

      expect(css).toMatchInlineSnapshot(`
        "@font-face {
        font-feature-settings: "smcp" on;
        ascent-override: 90%;
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        }
        "
      `)
    })

    test('Multiple weights default style', async () => {
      const { css } = await nextFontLocalFontLoader({
        functionName: '',
        data: [
          {
            style: 'italic',
            src: [
              {
                path: './fonts/font1.woff2',
                weight: '100',
              },
              {
                path: './fonts/font2.woff2',
                weight: '400',
              },
              {
                path: './fonts/font3.woff2',
                weight: '700',
              },
              {
                path: './fonts/font2.woff2',
                weight: '400',
                style: 'normal',
              },
            ],
            adjustFontFallback: false,
          },
        ],
        emitFontFile: () => `/_next/static/media/my-font.woff2`,
        resolve: jest.fn(),
        isDev: false,
        isServer: true,
        variableName: 'myFont',
        loaderContext: {
          fs: {
            readFile: (path: string, cb: any) => cb(null, path),
          },
        } as any,
      })

      expect(css).toMatchInlineSnapshot(`
        "@font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 100;
        font-style: italic;
        }

        @font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 400;
        font-style: italic;
        }

        @font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 700;
        font-style: italic;
        }

        @font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 400;
        font-style: normal;
        }
        "
      `)
    })

    test('Multiple styles default weight', async () => {
      const { css } = await nextFontLocalFontLoader({
        functionName: '',
        data: [
          {
            weight: '400',
            src: [
              {
                path: './fonts/font1.woff2',
                style: 'normal',
              },
              {
                path: './fonts/font3.woff2',
                style: 'italic',
              },
              {
                path: './fonts/font2.woff2',
                weight: '700',
              },
            ],
            adjustFontFallback: false,
          },
        ],
        emitFontFile: () => `/_next/static/media/my-font.woff2`,
        resolve: jest.fn(),
        isDev: false,
        isServer: true,
        variableName: 'myFont',
        loaderContext: {
          fs: {
            readFile: (path: string, cb: any) => cb(null, path),
          },
        } as any,
      })

      expect(css).toMatchInlineSnapshot(`
        "@font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 400;
        font-style: normal;
        }

        @font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 400;
        font-style: italic;
        }

        @font-face {
        font-family: myFont;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        font-weight: 700;
        }
        "
      `)
    })

    test('Custom font-family in declarations', async () => {
      const { css } = await nextFontLocalFontLoader({
        functionName: '',
        data: [
          {
            src: './my-font.woff2',
            declarations: [{ prop: 'font-family', value: 'Custom Font' }],
          },
        ],
        emitFontFile: () => '/_next/static/media/my-font.woff2',
        resolve: jest.fn(),
        isDev: false,
        isServer: true,
        variableName: 'myFont',
        loaderContext: {
          fs: {
            readFile: (_: string, cb: any) => cb(null, 'fontdata'),
          },
        } as any,
      })

      expect(css).toMatchInlineSnapshot(`
        "@font-face {
        font-family: Custom Font;
        src: url(/_next/static/media/my-font.woff2) format('woff2');
        font-display: swap;
        }
        "
      `)
    })
  })
})