JsonViewer

When to use

The JsonViewer component can be used for the display and editing of JSON data.

Semi mainly referred to the design concept of the text-buffer data structure of VS Code, reused some utilities and data type definitions (Token parsing, language services, etc.), and implemented the JsonViewer component in combination with our functional/style customization requirements. Visually, it will be more coordinated with other components within the Semi Design Next system, and it will be more convenient for customized rendering and customization of specific data types.

Compared with directly using MonacoEditor, Semi JsonViewer has additional processing in engineering construction, is simpler to use, and there is no need to pay attention to complex configurations such as Webpack plugins and worker loaders. At the same time, since we only focus on the JSON data format, it is more lightweight. While being ready to use out of the box, it has a smaller size (📦-96%), a more extreme loading speed (🚀 -53.5%), and less memory occupation (⬇️71.6% reduction). For data with five million lines and below, data loading and parsing can be completed within 1 second.

Detailed comparison data can be referred to in the Performance section.

• If you only need to preview/edit JSON and don't need to modify other more complex programming languages, we recommend that you choose JsonViewer.
• If you also need to handle data/code files in other formats and the full capabilities of a code editor (syntax highlighting, code completion, error prompts, complex editing, etc.) are essential and the build product size is not a key concern, we recommend that you choose Monaco Editor.

Demos

How to import

<script lang="ts">
    import { JsonViewer } from '@fibrae/semi-ui-svelte';
</script>

Basic Usage

Basic usage of JsonViewer. Pass height and width to set the height and width of the component, and pass the JSON string through value as the initial value. onChange is called with the editor's current text when the content changes. value can be bound with bind:value; the editor is re-created only when value becomes different from the editor's current content, so echoing the same content back keeps the caret; without a binding the editor keeps what the user typed. To read the value, call getValue() through bind:this (type JsonViewerHandle), please refer to Methods for details.

<script lang="ts">
    import { JsonViewer } from '@fibrae/semi-ui-svelte';

    const data = `{
    "name": "Semi",
    "version": "0.0.0"
}`;
</script>

<div style="margin-bottom: 16px">
    <JsonViewer height={100} value={data} width={700} />
</div>

Different lineHeight

Configure the lineHeight parameter of options to set a fixed line height (unit: px, default 20).

<script lang="ts">
    import { JsonViewer } from '@fibrae/semi-ui-svelte';

    const data = `{
    "name": "Semi",
    "version": "0.0.0"
}`;
    const wrapperStyle = 'margin-bottom: 12px; overflow: hidden';
</script>

<div>
    <div style={wrapperStyle}>
        <JsonViewer height={100} options={{ lineHeight: 20 }} value={data} width={700} />
    </div>
    <div style={wrapperStyle}>
        <JsonViewer height={120} options={{ lineHeight: 24 }} value={data} width={700} />
    </div>
    <div style={wrapperStyle}>
        <JsonViewer height={120} options={{ lineHeight: 26 }} value={data} width={700} />
    </div>
</div>

Autowrap

Configure the autoWrap parameter of options. When it is set to true, the component will automatically wrap lines according to the length of the content.

<script lang="ts">
    import { JsonViewer } from '@fibrae/semi-ui-svelte';

    const data = `{
    "name": "Semi",
    "version": "0.0.0",
    "description": "Semi Design is a design system that defines a set of mid_back design and front_end basic components."
}`;
    const options = { autoWrap: true };
</script>

<div style="margin-bottom: 16px">
    <JsonViewer height={120} {options} value={data} width={700} />
</div>

Format options

Configure options.formatOptions to set the formatting configuration of the component.

• tabSize: number，set the indent size to 4, which means each level of indentation is 4 spaces.
• insertSpaces: boolean，when it is true, it means using spaces for indentation, and when it is false, it means using tabs.
• eol: string，set the line break character, which can be \n，\r\n，

<script lang="ts">
    import { Button, JsonViewer, type JsonViewerHandle } from '@fibrae/semi-ui-svelte';

    const data = `{
  "name": "Semi",
  "version": "0.0.0"
}`;
    const options = { formatOptions: { tabSize: 4, insertSpaces: true, eol: '\n' } };

    let jsonviewer = $state<JsonViewerHandle>();
</script>

<div>
    <Button onclick={() => jsonviewer?.format()}>格式化</Button>
    <div style="margin-bottom: 16px; margin-top: 16px">
        <JsonViewer bind:this={jsonviewer} height={100} {options} value={data} width={700} />
    </div>
</div>

Custom Render Rules

By configuring the options.customRenderRule parameter, you can customize how JSON content is rendered (Note: only works in read-only mode).

Behavior notes

path in customRenderRule is computed more accurately: the key token and the value token of the same key-value pair share the same path (they both map to the property path, e.g. root.<key>).

As a result, rules that only rely on path (such as path === 'root.<key>') may match both the key and the value, which can change which rule “wins” compared to previous versions.

If you want to match only the key or only the value, use the third argument tokenType of function match:

const targetPath = 'root.<key>';
// Key only
match: (_value, path, tokenType) => tokenType === 'key' && path === targetPath;
// Value only
match: (value, path, tokenType) => tokenType === 'value' && path === targetPath;

customRenderRule is an array of rules that hold data only: match is the matching condition, and the optional name tells rules apart in the customRender snippet. The content of a matched token is drawn by {#snippet customRender({ item, index, content })}, where item is the matched rule and index is its position in customRenderRule.

• match: Matching condition, can be one of three types:
  • String: Exact match
  • Regular expression: Match by regex
  • Function: Custom matching logic, with signature (value: string | number | boolean | null, path: string, tokenType: 'key' | 'value') => boolean
    • value: Value to match (JSON key or value). When match is a function, value will be passed as the parsed primitive when possible (number / boolean / null / string), so strict comparisons like === work; when match is a string or RegExp, matching is still based on textual content (string tokens are unquoted)
    • path: Current matching path, format is root.key1.key2.key3[0].key4
    • tokenType: Current token type, 'key' for JSON property name, 'value' for JSON value. Useful for distinguishing between key and value matching

• name: Optional rule name; use item.name in the customRender snippet to tell rules apart
• customRender snippet: the arguments are { item, index, content }
  • content: Matched content. For string values, includes double quotes (e.g., "name", "Semi")
  • Without the snippet, or when it draws nothing, custom rendering is skipped and the token keeps its text

<script lang="ts">
    import { Image, JsonViewer, Popover, Rating, Tag, type JsonViewerOptions } from '@fibrae/semi-ui-svelte';

    const data = `{
  "name": "Semi",
  "version": "2.7.4",
  "rating": 5,
  "tags": ["design", "react", "ui"],
  "image": "/assets/root-web-sites/abstract.jpg"
}`;

    // A rule holds data only; the customRender snippet draws the token and tells the rules apart by name
    const options: JsonViewerOptions = {
        formatOptions: { tabSize: 4, insertSpaces: true, eol: '\n' },
        customRenderRule: [
            { name: 'popover', match: 'Semi' },
            { name: 'rating', match: (value) => value == 5 },
            {
                name: 'tag',
                match: (_value, path) => path === 'root.tags[0]' || path === 'root.tags[1]' || path === 'root.tags[2]',
            },
            { name: 'image', match: /^http/ },
        ],
        readOnly: true,
        autoWrap: true,
    };

    // content is the raw string token with its quotes; without them it is a valid URL
    const unquote = (content: string) => content.replace(/^"|"$/g, '');
</script>

{#snippet imagePreview(src: string)}
    <Image height={100} {src} width={100} />
{/snippet}

<div>
    <div style="margin-bottom: 16px; margin-top: 16px">
        <JsonViewer height={200} {options} showSearch={false} value={data} width={600}>
            {#snippet customRender({ item, content: text })}
                {#if item.name === 'popover'}
                    <Popover showArrow trigger="hover">
                        {#snippet content()}我是用户自定义的渲染{/snippet}
                        <span>{text}</span>
                    </Popover>
                {:else if item.name === 'rating'}
                    <Rating disabled size={10} value={Number(text)} />
                {:else if item.name === 'tag'}
                    <Tag shape="circle" size="small">{text}</Tag>
                {:else}
                    <Popover showArrow trigger="hover">
                        {#snippet content()}{@render imagePreview(unquote(text))}{/snippet}
                        <span>{text}</span>
                    </Popover>
                {/if}
            {/snippet}
        </JsonViewer>
    </div>
</div>

Custom Search Button

Use the searchButton snippet to customize the rendering of the search button, enabling fixed positioning, custom styles, and more. Providing the snippet replaces the default button as a whole; defaultButton is the default button's snippet, drawn with {@render defaultButton()}. When showSearch is false, neither is rendered.

<script lang="ts">
    import { IconSearch } from '@fibrae/semi-icons-svelte';
    import { Button, JsonViewer } from '@fibrae/semi-ui-svelte';

    const data = `{
    "name": "Semi",
    "version": "0.0.0"
}`;
</script>

<div style="margin-bottom: 16px">
    <JsonViewer height={200} value={data} width={700}>
        {#snippet searchButton({ defaultButton, showSearchBar, onToggleSearchBar })}
            <div style="position: absolute; top: 10px; right: 10px; z-index: 10">
                {#if !showSearchBar}
                    <Button onclick={onToggleSearchBar}>
                        {#snippet icon()}
                            <IconSearch />
                        {/snippet}
                        搜索
                    </Button>
                {:else}
                    {@render defaultButton()}
                {/if}
            </div>
        {/snippet}
    </JsonViewer>
</div>

API Reference

JsonViewer

Props

Methods

class, style and native attributes fall on the root element. The editor owns the root's content, so there is no children. When the root has no role and aria-label or aria-labelledby is passed, the root gets role="group"; an explicit role wins.

JsonViewerOptions

CustomRenderRule

The type is named JsonViewerCustomRenderRule. A rule holds data only; the content of a matched token is drawn by the customRender snippet.

FormattingOptions

CompletionOptions

SearchControls

With the searchButton snippet, the arguments (type JsonViewerSearchButtonArgs) contain the following properties besides defaultButton:

Methods

Methods exported by the component can be called through bind:this (type JsonViewerHandle), for example jsonviewer?.format().

Performance

Bundle Size

Time for rendering data of different magnitudes.

For details on the generation method of the test data, please refer to URL
When the data volume exceeds 500,000 lines, ReactMonacoEditor turns off highlighting and other behaviors by default, and the data comparison does not follow the principle of a single variable.