Function configure

Inject runtime configuration for jssm/viz — a custom DOMParser constructor for the *_svg_element functions, a replacement Graphviz engine for every render path, or both.

Each key is handled independently. Idempotent — last call wins per key; an omitted (or undefined) key leaves any earlier injection for that key in place, so neither injection can be un-set. No-op if called with no recognized keys.

Precedence differs by key, on purpose:

• DOMParser is a fallback — globalThis.DOMParser (browsers, jsdom test environments) still wins when present.
• viz is an override — once injected it is used for every render, and the default @viz-js/viz import is never even attempted. This is what lets WASM-hostile environments (strict-CSP webviews such as VS Code's markdown preview) supply an asm.js Graphviz build at runtime, without bundler aliasing. See VizEngine for the exact contract.

// Node, with jsdom:
import { JSDOM } from 'jsdom';
import { configure, fsl_to_svg_element } from 'jssm/viz';

configure({ DOMParser: new JSDOM().window.DOMParser });
const el = await fsl_to_svg_element('a -> b;');
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// strict-CSP webview, with an asm.js Graphviz:
import { configure, fsl_to_svg_string } from 'jssm/viz';

configure({ viz: my_asm_graphviz });  // anything with renderString(dot, opts)
const svg = await fsl_to_svg_string('a -> b;');
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