25 lines
891 B
JavaScript
25 lines
891 B
JavaScript
/**
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* Check if the given value is *inter-element whitespace*.
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*
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* @param {unknown} thing
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* Thing to check (typically `Node` or `string`).
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* @returns {boolean}
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* Whether the `value` is inter-element whitespace (`boolean`): consisting of
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* zero or more of space, tab (`\t`), line feed (`\n`), carriage return
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* (`\r`), or form feed (`\f`).
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* If a node is passed it must be a `Text` node, whose `value` field is
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* checked.
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*/
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export function whitespace(thing) {
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/** @type {string} */
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const value =
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// @ts-expect-error looks like a node.
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thing && typeof thing === 'object' && thing.type === 'text'
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? // @ts-expect-error looks like a text.
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thing.value || ''
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: thing
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// HTML whitespace expression.
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// See <https://infra.spec.whatwg.org/#ascii-whitespace>.
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return typeof value === 'string' && value.replace(/[ \t\n\f\r]/g, '') === ''
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}
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