23 lines
571 B
JavaScript
23 lines
571 B
JavaScript
/**
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* @typedef {import('hast').Nodes} Nodes
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*/
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/**
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* Get the rank (`1` to `6`) of headings (`h1` to `h6`).
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*
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* @param {Nodes} node
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* Node to check.
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* @returns {number | undefined}
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* Rank of the heading or `undefined` if not a heading.
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*/
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export function headingRank(node) {
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const name = node.type === 'element' ? node.tagName.toLowerCase() : ''
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const code =
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name.length === 2 && name.charCodeAt(0) === 104 /* `h` */
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? name.charCodeAt(1)
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: 0
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return code > 48 /* `0` */ && code < 55 /* `7` */
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? code - 48 /* `0` */
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: undefined
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}
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