import { sprintf } from 'sprintf-js'
// Regexes taken from or inspired by sprintf-js
const Regex = {
TEMPLATE_LITERAL: /\${([^)]+?)}/g,
KEY: /^([a-z_][a-z_\d]*)/i,
KEY_ACCESS: /^\.([a-z_][a-z_\d]*)/i,
INDEX_ACCESS: /^\[(\d+)\]/
}
/**
* imported from https://github.com/bigchaindb/js-utility-belt/
*
* Formats strings similarly to C's sprintf, with the addition of '${...}' formats.
*
* Makes a first pass replacing '${...}' formats before passing the expanded string and other
* arguments to sprintf-js. For more information on what sprintf can do, see
* https://github.com/alexei/sprintf.js.
*
* Examples:
* formatText('Hi there ${dimi}!', { dimi: 'Dimi' })
* => 'Hi there Dimi!'
*
* formatText('${database} is %(status)s', { database: 'BigchainDB', status: 'big' })
* => 'BigchainDB is big'
*
* Like sprintf-js, string interpolation for keywords and indexes is supported too:
* formatText('Berlin is best known for its ${berlin.topKnownFor[0].name}', {
* berlin: {
* topKnownFor: [{
* name: 'Currywurst'
* }, ...
* ]
* }
* })
* => 'Berlin is best known for its Currywurst'
*/
export default function formatText(s, ...argv) {
let expandedFormatStr = s
// Try to replace formats of the form '${...}' if named replacement fields are used
Eif (s && argv.length === 1 && typeof argv[0] === 'object') {
const templateSpecObj = argv[0]
expandedFormatStr = s.replace(Regex.TEMPLATE_LITERAL, (match, replacement) => {
let interpolationLeft = replacement
/**
* Interpolation algorithm inspired by sprintf-js.
*
* Goes through the replacement string getting the left-most key or index to interpolate
* on each pass. `value` at each step holds the last interpolation result, `curMatch` is
* the current property match, and `interpolationLeft` is the portion of the replacement
* string still to be interpolated.
*
* It's useful to note that RegExp.exec() returns with an array holding:
* [0]: Full string matched
* [1+]: Matching groups
*
* And that in the regexes defined, the first matching group always corresponds to the
* property matched.
*/
let value
let curMatch = Regex.KEY.exec(interpolationLeft)
if (curMatch !== null) {
value = templateSpecObj[curMatch[1]]
// Assigning in the conditionals here makes the code less bloated
/* eslint-disable no-cond-assign */
while ((interpolationLeft = interpolationLeft.substring(curMatch[0].length)) &&
value != null) {
if ((curMatch = Regex.KEY_ACCESS.exec(interpolationLeft))) {
value = value[curMatch[1]]
} else if ((curMatch = Regex.INDEX_ACCESS.exec(interpolationLeft))) {
value = value[curMatch[1]]
} else {
break
}
}
/* eslint-enable no-cond-assign */
}
// If there's anything left to interpolate by the end then we've failed to interpolate
// the entire replacement string.
if (interpolationLeft.length) {
throw new SyntaxError(
`[formatText] failed to parse named argument key: ${replacement}`
)
}
return value
})
}
return sprintf(expandedFormatStr, ...argv)
}
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