Refactor, units, tests

src/prepare.js

@@ -0,0 +1,71 @@
+const u = require('./utils')
+const a = require('./assert')
+
+const unnest = exports.unnest = (config) => {
+    if (a.type(config)() !== 'object') return config
+    const result = {}
+    for (const [key, val] of Object.entries(config)) {
+        u.deep(result, key, unnest(val))
+    }
+    return result
+}
+
+const _extend = exports._extend = (to, from) => {
+    const to_type = a.type(to)()
+    const from_type = a.type(from)()
+    if (from === undefined || from === null) return to
+    if (from === '!!unset') return undefined
+    if (to_type != from_type) return from
+    if (from_type == 'object') {
+        const res = u.deepcopy(to)
+        for (const key of Object.keys(from)) {
+            res[key] = _extend(to[key], from[key])
+            if (res[key] === undefined) delete res[key]
+        }
+        return res
+    } else if (from_type == 'array') {
+        const res = u.deepcopy(to)
+        for (const [i, val] of from.entries()) {
+            res[i] = _extend(res[i], val)
+        }
+        return res
+    } else return from
+}
+
+const extend = exports.extend = (...args) => {
+    let res = args[0]
+    for (const arg of args) {
+        if (res == arg) continue
+        res = _extend(res, arg)
+    }
+    return res
+}
+
+const _inherit = exports._inherit = (config, root, breadcrumbs) => {
+    if (a.type(config)() !== 'object') return config
+    const result = {}
+    for (const [key, val] of Object.entries(config)) {
+        breadcrumbs.push(key)
+        let newval = _inherit(val, root, breadcrumbs)
+        if (newval && newval.extends !== undefined) {
+            let candidates = [newval.extends]
+            const list = [newval]
+            while (candidates.length) {
+                const path = candidates.shift()
+                const other = u.deepcopy(u.deep(root, path))
+                a.assert(other, `"${path}" (reached from "${breadcrumbs.join('.')}.${key}.extends") does not name a valid target!`)
+                let parents = other.extends || []
+                if (a.type(parents)() !== 'array') parents = [parents]
+                candidates = candidates.concat(parents)
+                list.unshift(other)
+            }
+            newval = extend.apply(this, list)
+            delete newval.extends
+        }
+        result[key] = newval
+        breadcrumbs.pop()
+    }
+    return result
+}
+
+const inherit = exports.inherit = (config) => _inherit(config, config, [])